Don't save widget default titles

[guimafelipe]

Summary of the pull request

When the user saves a widget with not title, a default title is displayed for them. For repository widgets, it is the name of the repository. For user widgets, it is the username. This title was being saved in the widget data, but resulted is some QoL issues. This PR makes these default titles to not be saved anymore, and just rendered in the content is loaded to be presented.

References and relevant issues

Detailed description of the pull request / Additional comments

As the issue above describes, when the user saves a repository widget, it sets the title to be its repository's full name. When the user customizes this widget and changes to another repository, the previous title keeps saved, requiring the user to actively change or erase the title.
This default title does not need to be saved as it is a information that we get on time from the widget's information. So it is the best choice to not save it in the widget's data string and just generate the string when it is needed.

Validation steps performed

PR checklist

• Closes Update widget title after repo update #430
• Tests added/passed
• Documentation updated

[krschau]

I renamed the PR since the original wording made it sound like a bug, instead of a fix to the bug.