Normalize Uris when writing manifests

[michellemcdaniel]

For each manifest, we should normalize the Azure DevOps uris, so that differences between machine state do not affect merging the manifests down the line. We will normalize the AzureDevOpsRepository and the InitialAssetsLocations, if found in the attributes.

Fixes #7493.

To double check:

• The right tests are in and and the right validation has happened. Guidance: https://github.com/dotnet/core-eng/tree/master/Documentation/Validation

[riarenas]

Can we add tests for this to https://github.com/dotnet/arcade/blob/main/src/Microsoft.DotNet.Build.Tasks.Feed.Tests/BuildModelFactoryTests.cs?

[michellemcdaniel]

I wasn't sure exactly how to fit it in, but I will try.

[michellemcdaniel]

Updated the tests with the new normalization info.