Remove commit message 50 character soft limit

What does this MR do?

Our commit message guidelines and Danger always mention that commit messages should ideally be less than 50 characters in length. I have seen mention of people disliking this in Slack in the past but I'm not sure if anyone has proposed we remove that guideline.

I personally have never ran into the 72 character limit, but I often exceed the 50 character limit. I can't think of a reason why we would prefer the message be less than 50 characters. In fact, needlessly shortening the commit message could make it more difficult to understand what the change was about.

Screenshots

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• 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

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• Label as security and @ mention @gitlab-com/gl-security/appsec
• The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• Security reports checked/validated by a reviewer from the AppSec team