Migrate link_to buttons to Pajamas buttons in commits_helper.rb

What does this MR do and why?

Migrate link_to buttons to Pajamas buttons in commits_helper.rb

Screenshots or screen recordings

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Commit page
Commits list view

How to set up and validate locally

Go to a commit (eg http://localhost:3000/gitlab-org/gitlab-test/-/commit/ddd0f15ae83993f5cb66a927a28673882e99100b)

• Check Browse files button in top right page
• Check View <sha> button in top right of file

Go to commits page (eg http://localhost:3000/gitlab-org/gitlab-test/-/commits/master_

• Check Browse files folder icon button on far right of each commit

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Migrate to Pajamas compliant buttons in app/hel... (#417797 - closed)