Allow manual dispatch for E2E and accessibility tests

[omarayman23]

[#13356] Make E2E and accessibility tests run manually Fixes #13356 Outline of Solution This PR updates the GitHub Actions workflow files to prevent expensive E2E and accessibility tests from running on every commit.

• Changed axe.yml, e2e.yml, and e2e-sql.yml to be triggered manually via workflow_dispatch: instead of on push and pull_request.
• The schedule: for the E2E tests is kept, so they will still run daily.
• This resolves the issue where developers had to run a full test suite for minor changes or when merging master.

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