Improve error message when Dagger compiler not run over module

[arimu1]

Summary

When a @Module lives in a dependency that was compiled without the Dagger annotation processor / KSP plugin, generated component code references missing *Factory types and the user only sees a vague javac "does not exist" error.

This PR detects that situation during component validation and reports a clear diagnostic:

The Dagger factory type lib.LibraryModule_ProvideStringFactory is missing. This usually means the Dagger compiler was not applied to the module lib.LibraryModule where the binding is defined. Ensure that the dependency that contains that module runs the Dagger annotation processor (or KSP plugin).

Approach (aligned with option 1 from #5146, using the existing knownModules set so it works for both Javac and KSP):

• Modules processed in the current compilation are recorded via ModuleValidator.addKnownModules (as before).
• For transitive modules on a component that are not from the current compilation, require that each @Provides / @Produces factory exists on the classpath.
• Skip modules from the current compilation: their factories are generated in-round by ModuleProcessingStep and may not yet be visible via findTypeElement.
• @Binds-only modules do not require factories and are unaffected.

Fixes #5146

Test plan

• bazel test //javatests/dagger/internal/codegen:ModuleMissingFactoryErrorTest
• bazel test //javatests/dagger/internal/codegen:AssistedFactoryTest
• bazel test //javatests/dagger/internal/codegen:ModuleValidationTest
• No open prior PR for Better error message when Dagger compiler not run over module. #5146 (re-checked before open)