Proposed Changes

The workflow "Regression tests running on Linux ARM64" seems to have always timed out after 24 hours of looking for a runner, and has attempted to run on every merge into develop.

This PR:

• Fixes the runner name according to the available runners for public repos
• Adds a workflow_dispatch trigger to allow manually triggering on either of the available runners
• Updates the test values for aarch64 regressions
• Adds a TestCase.tol_aarch64 in the regression Python script for cases where a larger tolerance is needed than in the x86_64 regressions

PR Checklist

• I am submitting my contribution to the develop branch.
• My contribution generates no new compiler warnings (try with --warnlevel=3 when using meson).
• My contribution is commented and consistent with SU2 style (https://su2code.github.io/docs_v7/Style-Guide/).
• I used the pre-commit hook to prevent dirty commits and used pre-commit run --all to format old commits.
• I have added a test case that demonstrates my contribution, if necessary.
• I have updated appropriate documentation (Tutorials, Docs Page, config_template.cpp), if necessary.