When building AutoValue, pick up AutoService via `<annotationProcessorPaths>`.
When building AutoValue, pick up AutoService via `<annotationProcessorPaths>`.

The annotation dependencies for `@AutoService` and for Error Prone are now regular compile-scoped dependencies. This prevents errors from overeager consumers that can't deal with missing annotation class files.

The `<annotationProcessorPaths>` incantations are kind of clunky since we need a different path for building tests (which must include AutoValueProcessor) and for building AutoValue itself (which obviously can't).

Fixes https://github.com/google/auto/issues/1032.

RELNOTES=n/a
PiperOrigin-RevId: 367010584

eamonnmcmanus/auto,google/auto,eamonnmcmanus/auto,eamonnmcmanus/auto,google/auto,google/auto