Update "unable to save" warning to use modal pattern

[jeromeleecms]

Update the "unexpected error saving" message to use the modal pattern provided by design.cms.gov

Update the text on the save changes error pop-up

Header: Unable to save changes!

Body: Your changes aren't being saved. Try saving your changes again in a few minutes by clicking on the save button. If you refresh your browser without saving backing up your changes, changes made after this message appeared will be lost.

This task is done when...

• Old message pattern is removed
• "Unexpected error saving" now uses the modal pattern
• Update the text in the modal to the above header/body text

[beparticular]

Here is the language from the closed design ticket to use on this modal. I'm not sure what the corresponding dev ticket is and didn't find a duplicate. [Update: here is the duplicate #2803.]

Header: Unable to save changes!

Body: Your changes aren't being saved. Try saving your changes again in a few minutes by clicking on the save button. If you refresh your browser without saving or backing up your changes, changes made after this message appeared will be lost.

[eStar386]

QA Passed: Verified that the modal appeared when applicable at the top of the header/body text.

[eStar386]

Please use the test script when testing in addition to any personal methods https://drive.google.com/file/d/1cazcjKnuzwWaipu5iHaooZDsbYJG9wJr/view?usp=sharing