Improve vendor dep error handling for malformed files

[sciencewhiz]

Does not parse hidden files. Fixes wpilibsuite/GradleRIO#726
Identifies file that failed to load or parse

[sciencewhiz]

The error printed before was from deep within GSON, such as:

An exception occurred applying plugin request [id: 'edu.wpi.first.GradleRIO', version: '2024.2.1']
> Failed to apply plugin class 'edu.wpi.first.gradlerio.wpi.WPIPlugin'.
   > Could not create an instance of type edu.wpi.first.gradlerio.wpi.WPIExtension.
      > java.nio.charset.MalformedInputException: Input length = 1

now its:

An exception occurred applying plugin request [id: 'edu.wpi.first.GradleRIO', version: '2025.1.1-beta-1-8']
> Failed to apply plugin class 'edu.wpi.first.gradlerio.wpi.WPIPlugin'.
   > Could not create an instance of type edu.wpi.first.gradlerio.wpi.WPIExtension.
      > Failed to parse vendor dependency: ._REVLib.json