Don't raise missing properties diagnostic if assigned object value has an additional properties type

[jeskew]

Resolves #13247

The type narrowing on objects introduced in #12798 will erroneously raise a missing property diagnostic if the assigned value does not have an explicit property defined for each of the target's required properties, even if the assigned value allows additional properties. This PR updates the type narrowing to consider required properties not to be missing if the assigned value allows arbitrary additional properties.

Microsoft Reviewers: Open in CodeFlow

[github-actions]

Test this change out locally with the following install scripts (Action run 7840455291)

VSCode

• Mac/Linux

  bash <(curl -Ls https://aka.ms/bicep/nightly-vsix.sh) --run-id 7840455291

• Windows

  iex "& { $(irm https://aka.ms/bicep/nightly-vsix.ps1) } -RunId 7840455291"

Azure CLI

• Mac/Linux

  bash <(curl -Ls https://aka.ms/bicep/nightly-cli.sh) --run-id 7840455291

• Windows

  iex "& { $(irm https://aka.ms/bicep/nightly-cli.ps1) } -RunId 7840455291"

[github-actions]

Test Results

    66 files   -     33      66 suites   - 33   24m 45s ⏱️ - 28m 37s
11 008 tests  -     19  11 008 ✅  -     19  0 💤 ±0  0 ❌ ±0 
25 906 runs   - 12 946  25 906 ✅  - 12 946  0 💤 ±0  0 ❌ ±0 

Results for commit 7d9383a. ± Comparison against base commit 83ce3e5.

♻️ This comment has been updated with latest results.