Drop `HasSourcePath` in favor of `FindSourceFiles`

[timtebeek]

What problem are you trying to solve?

Both recipes do the same in slightly different ways; rather than maintain both we want to only have one going forward. Logging here, but should also be updated downstream.

Describe the solution you'd like

HasSourcePath fully removed, here and downstream, where it can be replaced with FindSourceFiles.

• [x] Evaluate if any downstream projects use the HasSourcePath regex option, and if so add that to FindSourceFiles.
• [x] Replace HasSourcePath with FindSourceFiles downstream.
• [x] Remove HasSourcePath here.

Additional context

• 3749

[timtebeek]

Turns out HasSourcePath supported {.md,.txt} syntax, which FindSourceFiles does not (yet) support. Worked around this in downstream projects where we saw test failures; did not spot this elsewhere.

• https://github.com/openrewrite/rewrite-spring/commit/fa4e1c9c20d7373ea1d5d3bf1fdf44a29ab6c537
• https://github.com/openrewrite/rewrite-micronaut/commit/c1c0ebd5637b1f145a4bc5f3d4b87d71a4114199