build: Update permissions at top level and add environment

[oZakari]

Overview/Summary

This pull request includes several updates to the GitHub Actions workflows to adjust permissions and environment settings. The most important changes are grouped by theme below:

Permissions updates:

• .github/workflows/bicep-build-to-validate.yml: Added permissions block with contents: read.
• .github/workflows/gh-ado-sync.yml: Added permissions block with contents: read.
• .github/workflows/release-tests.yml: Added permissions block with contents: read.
• .github/workflows/scheduled-bicep-build.yml: Re-added permissions block with contents: read after the on block.

Environment settings:

• .github/workflows/psdocs-mdtogit.yml: Added environment: BicepUpdateDocumentation under the jobs block.

Related Issues/Work Items

N/A

Breaking Changes

None

Testing Evidence

Replace this with any testing evidence to show that your Pull Request works/fixes as described and planned (include screenshots, if appropriate).

As part of this Pull Request I have

• Read the Contribution Guide and ensured this PR is compliant with the guide
• Ensured the resource API versions in .bicep file/s I am adding/editing are using the latest API version possible
• Checked for duplicate Pull Requests
• Associated it with relevant GitHub Issues
• (ALZ Bicep Core Team Only) Associated it with relevant ADO Items
• Ensured my code/branch is up-to-date with the latest changes in the main branch
• Performed testing and provided evidence.
• Updated one or more of the following tests (if required)
  • Unit
  • Linting
  • E2E (End-To-End)
  • ValidateAzCloud (Base validation in Azure Cloud)
  • ValidateMcCloud (Base validation in Azure China Cloud)
• Updated relevant and associated documentation (e.g. Contribution Guide, Module READMEs, Wiki Docs etc.)
• If relevant, created or updated Code Tours here