perf(dotnet): fail faster in the dotnet module

[davidkna]

Description

For finding the necessary files to determine the version and if the module should be enabled the dotnet module is currently iterating through all files in the current directory (O(n)) to find relevant files.

This PR makes the module exit early in case the relevant files aren't present and only does the work of finding these files if they are present.

Possible breakage:
estimate_dotnet_version is case insentive but context.is_match() is not.

Motivation and Context

Tested with hyperfine in starship/src/modules:

before:
starship module dotnet 63.9 ms ± 4.6 ms

after:
starship module dotnet 23.9 ms ± 2.5 ms

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Screenshots (if appropriate):

How Has This Been Tested?

• I have tested using MacOS
• I have tested using Linux
• I have tested using Windows

Checklist:

• I have updated the documentation accordingly.
• I have updated the tests accordingly.

[davidkna]

It looks like #886 wasn't fixed after all.

[matchai]

Thank you for the performance improvement, @davidkna! 😄