Permit validation for property access on union types

[anthony-c-martin]

Closes #9736

Microsoft Reviewers: Open in CodeFlow

[github-actions]

Test this change out locally with the following install scripts (Action run 8971960608)

VSCode

• Mac/Linux

  bash <(curl -Ls https://aka.ms/bicep/nightly-vsix.sh) --run-id 8971960608

• Windows

  iex "& { $(irm https://aka.ms/bicep/nightly-vsix.ps1) } -RunId 8971960608"

Azure CLI

• Mac/Linux

  bash <(curl -Ls https://aka.ms/bicep/nightly-cli.sh) --run-id 8971960608

• Windows

  iex "& { $(irm https://aka.ms/bicep/nightly-cli.ps1) } -RunId 8971960608"

[github-actions]

Test Results

    64 files   -     35      64 suites   - 35   22m 24s ⏱️ - 9m 8s
10 878 tests  -     19  10 877 ✅  -     19  1 💤 ±0  0 ❌ ±0 
25 652 runs   - 12 819  25 650 ✅  - 12 818  2 💤  - 1  0 ❌ ±0 

Results for commit 1328b45. ± Comparison against base commit 1c6b9b5.

♻️ This comment has been updated with latest results.