Minor Fixes

[gvatsal60]

This pull request updates CI workflows and pre-commit hooks to improve automation and streamline linting. The main changes include simplifying auto-approval and merge steps for bot-generated PRs, removing a redundant workflow, and updating pre-commit hooks to focus on essential checks while adding dedicated Markdown linting.

CI workflow improvements:

• Combined approval and auto-merge steps into a single step using squash merges for both Dependabot and pre-commit PRs in .github/workflows/dependabot-pr.yaml and .github/workflows/pre-commit-pr.yaml. Also, added an extra check to ensure the PR author is of type Bot. [1] [2]
• Removed the .github/workflows/readme-checker.yaml workflow, which previously handled Markdown linting.

Pre-commit hook configuration updates:

• Removed several less essential hooks from .pre-commit-config.yaml, such as check-ast, check-toml, check-xml, and others, to streamline checks.
• Added the markdownlint-cli2 hook for Markdown linting, replacing the removed workflow with a pre-commit solution.