[rush] Expose hasUncommittedChanges flag on input snapshot

[dmichon-msft]

Summary

Adds a flag hasUncommittedChanges to the metadata for the input snapshot that plugins can use to identify if the current repository state has uncommitted changes. This is useful if trying to tie state to a git commit.

Details

Adds getDetailedRepoStateAsync API to @rushstack/package-deps-hash to expose hasUncommittedChanges and hasSubmodules in addition to the existing files map. The information to compute these fields was already available in the calculation of getRepoStateAsync.

Updates getRepoStateAsync to just be a wrapper around getDetailedRepoStateAsync that extracts and returns the files property.

How it was tested

Updated the existing unit tests for getRepoStateAsync to instead operate on the expanded data of getDetailedRepoStateAsync.

Impacted documentation

The API doc for @rushstack/package-deps-hash, API for IInputsSnapshot in rush-lib.