Fix TypeScript linting.
Fix TypeScript linting.

Speeds up eslint because it prefers the application
tsconfig.json over the project wide tsconfig.json.

Change-Id: I9f1d5d6711d44b107324a518ad2e3fd757e752ec
Reviewed-on: https://skia-review.googlesource.com/c/buildbot/+/374039
Reviewed-by: Joe Gregorio <b9cf2471ff6d33504cafe8e6f356b732b2cadced@google.com>

google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot