Fix missing VMR assets in SiteExtensions packages

[wtgodbe]

Should fix #61185, #61187.

Current test build: https://dev.azure.com/dnceng/internal/_build/results?buildId=2674842&view=results

After this change:

Issues: 1217
Baselined issues: 837
Detailed issue counts by type:
MissingShipping: Issues w/o Baseline = 338, Baselined issues = 96
MissingNonShipping: Issues w/o Baseline = 114, Baselined issues = 0
MisclassifiedAsset: Issues w/o Baseline = 2, Baselined issues = 0
AssemblyVersionMismatch: Issues w/o Baseline = 5, Baselined issues = 741
MissingPackageContent: Issues w/o Baseline = 435, Baselined issues = 0
ExtraPackageContent: Issues w/o Baseline = 9, Baselined issues = 0
PackageMetadataDifference: Issues w/o Baseline = 237, Baselined issues = 0
PackageTFMs: Issues w/o Baseline = 1, Baselined issues = 0
PackageDependencies: Issues w/o Baseline = 76, Baselined issues = 0