Fix CI editor template not updating on commit

What does this MR do?

When the default content is loaded for the pipeline editor, there was an issue where changing the content of the file would not be saved when you commit. This was due to using a computed prop to store the content: if it was a new file, we were using the template, and if not, we were using the normal content. However when the user starts typing, it is still a new Ci config file, so the content was never properlyupdated in hte global store.

Screenshots (strongly suggested)

Before	After
Screen_Recording_2021-06-14_at_3.03.55_PM	editor_load

Does this MR meet the acceptance criteria?

Conformity

• I have included changelog trailers, or none are needed. (Does this MR need a changelog?)
• I have added/updated documentation, or it's not needed. (Is documentation required?)
• [-] I have properly separated EE content from FOSS, or this MR is FOSS only. (Where should EE code go?)
• [-] I have added information for database reviewers in the MR description, or it's not needed. (Does this MR have database related changes?)
• I have self-reviewed this MR per code review guidelines.
• This MR does not harm performance, or I have asked a reviewer to help assess the performance impact. (Merge request performance guidelines)
• I have followed the style guides.
• This change is backwards compatible across updates, or this does not apply.

Availability and Testing

• I have added/updated tests following the Testing Guide, or it's not needed. (Consider all test levels. See the Test Planning Process.)
• I have tested this MR in all supported browsers, or it's not needed.
• I have informed the Infrastructure department of a default or new setting change per definition of done, or it's not needed.