Mattermost-server: Improve Announcement banner tooltip behavior

[mattermod]

Announcement banner display tooltips to show the content when it exceeds one line and is truncated. The current behavior is redundant and always show tooltips for Announcement banners even when the text isn't truncated.

Observed
Tooltips always display when a user hovers over an Announcement banner, even when the text isn't truncated.

Expected

• Only show the tooltip if the text in the banner truncates
• Fix the z-index of the tooltip, it sits behind the banner

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JIRA: https://mattermost.atlassian.net/browse/MM-16068

[fullstackguyhere]

@hanzei would like to take this up.

[fullstackguyhere]

@amyblais could you share the screenshot mentioned in the description. I am unable to see it.

[amyblais]

/cc @esethna ^

[esethna]

@amyblais @fullstackguyhere updated. Image is in the JIRA ticket linked. Thanks for taking the ticket :)

[fullstackguyhere]

@esethna @hanzei @amyblais I have PR ready for this, I have submitted my details by accepting Mattermost Contributor License Agreement. Could anyone accept it so that I can submit my PR?

[jasonblais]

@fullstackguyhere no need to wait, and I've now confirmed the CLA is submitted correctly. Feel free to go ahead with the PR :tada:

Huge thank you for the help!

[fullstackguyhere]

Thanks @jasonblais, will do it today.

[fullstackguyhere]

done @jasonblais