ci: use built-in token for team-memory dispatch

[Changyong Gong (chagong)]

Known cross-repository authorization blocker — DRAFT / NOT MERGE-READY: ${{ github.token }} is scoped to microsoft/vscode-maven and does not have Actions-write access to microsoft/vscode-java-pack. Job-level actions: write does not expand the token's repository scope. This user-directed substitution is not a working, proven cross-repository dispatch replacement and must not be merged as-is. Java Pack's own-source workflow uses a same-repository token; that reference, a public read diagnostic, and passing CI do not establish caller write authorization.

Requested change

• Remove the actions/create-github-app-token dispatch-token mint step and its App credential references.
• Set dispatch-job permissions to contents: read / actions: write, preserving top-level permissions: {}.
• Pass ${{ github.token }} to the queue action, following the wiring in Java Pack's main .github/workflows/team-memory-post-merge.yml.

Preserved scope and behavior

Only .github/workflows/team-memory-post-merge.yml changes, based on current default main (d83e339b4a1cbeb7ba3f39fbabce179786909a23), not the former #1224 feature branch. All eight opt-in/canonical-source/default-push/workflow-head/non-created/non-deleted/non-forced gates remain unchanged. The immutable IssueLens action pin, explicit Java Pack coordinator repository/workflow/main target, and exact five string-valued JSON inputs remain unchanged. No documentation, credentials, opt-in settings, architecture, fallback, or unrelated workflows are changed. Production remains unchanged; no merge or auto-merge is requested.

Validation

Offline PyYAML parsing with duplicate-key rejection and structural assertions passed. Comparison against the fetched main workflow confirms exactly the requested semantic changes; checks verify the preserved gates, action pin, coordinator target, JSON payload, permissions, removal of dangling token-output/credential references, and workflow-only file scope. git diff --check passed. No live token mint, coordinator POST/dispatch, or rerun was performed; these checks do not verify cross-repository dispatch authorization.