[39/44] Enable TS strict mode in portlets-content-drive

Description

Part of the strict-mode rollout epic #35932. Enable TypeScript strict mode for the portlets-content-drive project using typescript-strict-plugin.

• Dependency layer: 7 (0 = leaf library, 10 = top-level app)
• Internal dependents: 1 project(s)
• Rollout order: 39 / 44

All internal dependencies of portlets-content-drive should already be in strict mode before starting (they appear earlier in the rollout order).

Acceptance Criteria

• portlets-content-drive's src is added to the typescript-strict-plugin strict paths config.
• All resulting type errors are resolved (no new any; use explicit types).
• // @ts-strict-ignore is used only where unavoidable, each with a follow-up TODO.
• yarn nx run portlets-content-drive:lint passes (and :build / :test where applicable).
• npx tsc-strict passes for portlets-content-drive.
• yarn nx affected -t build does not break dependents.

Priority

Medium

Additional Context

One project in the bottom-up rollout tracked by epic #35932. Depends on the bootstrap task being merged and on lower-layer projects already being strict.

Confirm the bootstrap task and lower-layer strict-mode projects from epic #35932 are merged, then inspect the typescript-strict-plugin strict paths config and the portlets-content-drive src tree. Add the project path, run npx tsc-strict, and resolve the reported errors with explicit types. Done means strict checking passes without unjustified ignores, and the listed lint, build, test, and affected-build commands succeed.