Fix overflow UI bug with longer commit title on Wiki Page History

What does this MR do?

Fixes a bug overflowing with longer commit title of the Git commit in Wiki repository on Wiki Page History. In fact this replaces str-truncated-60 class with .commit-content in app/views/shared/wikis/history.html.haml as part of #326634 (closed).

Screenshots (strongly suggested)

before	after

Does this MR meet the acceptance criteria?

Conformity

• 📋 Does this MR need a changelog?
  • I have included a changelog entry.
• [n/a] Documentation (if required)
• Code review guidelines
• [n/a] Merge request performance guidelines
• Style guides
• [n/a] Database guides
• Separation of EE specific content

Availability and Testing

• [-] Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• [-] Tested in all supported browsers
• [-] Informed Infrastructure department of a default or new setting change, if applicable per definition of done

Closes #326636 (closed)