Resolve AMP violations in header and description for Modal

[Bibek-Regmi]

Description

Allow users to define header level for title Use given id for title and description to prevent duplicate modals from causing violations

Motivation and Context

Type of Change (Select One and Apply Github Label)

• [ ] Bug fix (non-breaking change which fixes an issue) -> Apply bugfix label
• [ ] New feature (non-breaking change which adds functionality) -> Apply enhancement label
• [ ] Breaking change (fix or feature that would cause existing functionality to change) -> Apply breaking label

Screenshots (if appropriate):

Which browsers have you tested?

• [ ] Internet Explorer 11
• [ ] Edge
• [ ] Chrome
• [ ] Firefox
• [ ] Safari

Checklist:

• [ ] I have read the (https://github.comv/GSA/sam-ui-elements/blob/CONTRIBUTING.md)[CONTRIBUTING.md] document.
• [ ] My code passes the automated linter.
• [ ] This code has been reviewed by another team member and passes the reviewer checklist found in (https://github.comv/GSA/sam-ui-elements/blob/CONTRIBUTING.md)[CONTRIBUTING.md]
• [ ] My change requires a change to the documentation.
• [ ] I have updated the documentation accordingly.
• [ ] I have added tests to cover my changes.
• [ ] All new and existing tests passed.
• [ ] My code is 508 compliant as tested by AMP and JAWS
• [ ] Any dependent changes have been merged and published in downstream modules