[task] fix circular dependencies from 'task' extension

[vince-fugnitto]

What it does

Fixes the circular dependencies present from the @theia/task extension:

• Remove the circular dependency.
• Export the moved classes from the original file not to break consumers.

Before	After

How to test

• Verify that CI successfully passes (build & tests of the @theia/task extension).
• Verify that clicking the Configure icon (cog) still works correctly when selecting Run Tasks....

Review checklist

• as an author, I have thoroughly tested my changes and carefully followed the review guidelines

Reminder for reviewers

• as a reviewer, I agree to behave in accordance with the review guidelines

Signed-off-by: Vincent Fugnitto [email protected]

[vince-fugnitto]

I don't have a strong opinion on this.
If others find that this is not a real problem or unnecessary then I do not object if it is closed :)

[elaihau]

I have no issues with this change. but having Roman's opinion is preferable, as he was the person who did the task action provider.

[RomanNikitenko]

I checked that Configure icon (cog) still works correctly.

@vince-fugnitto
thank you for fix!

[vince-fugnitto]

Thank you @elaihau @RomanNikitenko !