Refactor validateWorkspace to handle missing custom scalafmtConfigPath gracefully and log warning

[Austinito]

PR Overview

This PR refactors the validateWorkspace function to gracefully handle missing scalafmtConfigPath files. Previously, this scenario would result in uncaught exceptions.

Example Logs

2024.12.31 11:48:07 ERROR Failed to connect with build server, no functionality will work.
java.nio.file.NoSuchFileException: {dir}/akka-quickstart-scala/.my_scalafmt.conf
	at sun.nio.fs.UnixException.translateToIOException(UnixException.java:92)
	at sun.nio.fs.UnixException.rethrowAsIOException(UnixException.java:106)
	at sun.nio.fs.UnixException.rethrowAsIOException(UnixException.java:111)
	at sun.nio.fs.UnixFileSystemProvider.newByteChannel(UnixFileSystemProvider.java:218)
	at java.nio.file.Files.newByteChannel(Files.java:380)
	at java.nio.file.Files.newByteChannel(Files.java:432)
	at java.nio.file.Files.readAllBytes(Files.java:3288)
	at scala.meta.internal.io.PlatformFileIO$.slurp(PlatformFileIO.scala:42)
	at scala.meta.internal.io.FileIO$.slurp(FileIO.scala:18)
	at scala.meta.internal.mtags.ScalametaCommonEnrichments$XtensionAbsolutePath.toInput(ScalametaCommonEnrichments.scala:445)
	at scala.meta.internal.metals.MetalsEnrichments$XtensionAbsolutePathBuffers.toInputFromBuffers(MetalsEnrichments.scala:621)
	at scala.meta.internal.metals.FormattingProvider.validateWorkspace(FormattingProvider.scala:408)

The refactor:

• Wraps .toInputFromBuffers in a Try to catch errors.
• Logs a warning when custom scalafmtConfigPath is missing.
• Returns None instead of throwing exceptions, improving stability and providing clear feedback.

Key Changes

• Added handling for missing scalafmtConfigPath.
• Refactored validateWorkspace to use a safer text extraction approach.

Rationale

Improves robustness and user experience by ensuring the absence of scalafmtConfigPath is handled gracefully with logging instead of crashes.

Stemmed from discussion in nvim-metals (logs included):

[tgodzik]

Thanks! LGTM

I pushed one last commit to run scalafix