chore: remove ecosystem-ci-gate workflow (#17795)

The app shared between Kit and Svelte takes care of this now

### Before submitting the PR, please make sure you do the following

- [ ] It's really useful if your PR references an issue where it is
discussed ahead of time. In many cases, features are absent for a
reason. For large changes, please create an RFC:
https://github.com/sveltejs/rfcs
- [ ] Prefix your PR title with `feat:`, `fix:`, `chore:`, or `docs:`.
- [ ] This message body should clearly illustrate what problems it
solves.
- [ ] Ideally, include a test that fails without this PR but passes with
it.
- [ ] If this PR changes code within `packages/svelte/src`, add a
changeset (`npx changeset`).

### Tests and linting

- [ ] Run the tests with `pnpm test` and lint the project with `pnpm
lint`

.github/workflows/ecosystem-ci-gate.yml

@@ -1,108 +0,0 @@
-name: ecosystem-ci gate
-
-on:
-  pull_request:
-    types: [opened, reopened, synchronize, ready_for_review]
-  issue_comment:
-    types: [created]
-
-permissions: {}
-
-jobs:
-  gate:
-    if: github.repository == 'sveltejs/svelte' && ((github.event_name == 'pull_request' && github.event.pull_request.head.ref == 'changeset-release/main') || (github.event_name == 'issue_comment' && github.event.issue.pull_request && startsWith(github.event.comment.body, '/ecosystem-ci run')))
-    runs-on: ubuntu-latest
-    permissions:
-      pull-requests: read
-      issues: read
-      contents: read
-    steps:
-      - name: Evaluate gate
-        id: evaluate
-        uses: actions/github-script@v8
-        with:
-          script: |
-            const allowed_roles = new Set(['admin', 'maintain', 'write'])
-
-            const pull_number = context.payload.pull_request
-              ? context.payload.pull_request.number
-              : context.issue.number
-
-            const { data: pr } = await github.rest.pulls.get({
-              owner: context.repo.owner,
-              repo: context.repo.repo,
-              pull_number,
-            })
-
-            const is_release_pr = pr.head.ref === 'changeset-release/main'
-            if (!is_release_pr) {
-              core.notice(`PR #${pull_number} is not a release PR (${pr.head.ref}). Gate not required.`)
-              core.setOutput('should_fail', 'false')
-              core.setOutput('reason', 'Gate is only required for changeset-release/main')
-              return
-            }
-
-            const { data: commits } = await github.rest.pulls.listCommits({
-              owner: context.repo.owner,
-              repo: context.repo.repo,
-              pull_number,
-              per_page: 250,
-            })
-
-            const last_commit = commits[commits.length - 1]
-            const last_commit_time = new Date(last_commit.commit.committer.date)
-
-            const comments = await github.paginate(github.rest.issues.listComments, {
-              owner: context.repo.owner,
-              repo: context.repo.repo,
-              issue_number: pull_number,
-              per_page: 100,
-            })
-
-            let has_valid_command = false
-            for (const comment of comments) {
-              if (!(comment.body || '').trim().startsWith('/ecosystem-ci run')) {
-                continue
-              }
-
-              const comment_time = new Date(comment.created_at)
-              if (comment_time <= last_commit_time) {
-                continue
-              }
-
-              let permission
-              try {
-                const { data } = await github.rest.repos.getCollaboratorPermissionLevel({
-                  owner: context.repo.owner,
-                  repo: context.repo.repo,
-                  username: comment.user.login,
-                })
-                permission = data.permission
-              } catch {
-                permission = 'none'
-              }
-
-              if (allowed_roles.has(permission)) {
-                has_valid_command = true
-                break
-              }
-            }
-
-            if (has_valid_command) {
-              core.setOutput('should_fail', 'false')
-              core.setOutput('reason', 'Valid maintainer /ecosystem-ci run command found after latest commit')
-              return
-            }
-
-            core.setOutput('should_fail', 'true')
-            core.setOutput('reason', 'Release PRs require a maintainer to run /ecosystem-ci after the latest commit')
-
-      - name: Enforce gate
-        if: steps.evaluate.outputs.should_fail == 'true'
-        run: |
-          echo "${{ steps.evaluate.outputs.reason }}"
-          exit 1
-
-      - name: Gate satisfied
-        if: steps.evaluate.outputs.should_fail != 'true'
-        run: echo "${{ steps.evaluate.outputs.reason }}"