Add 'X' to alert danger banner

• Type: Regression Bug
• Status: Closed
• Resolution: Fixed
• Affects Version/s: Master
• Fix Version/s: 7.1.10 DXP FP12, 7.1.X, Master
• Component/s: ~ [Archived] Frontend Infrastructure
• Labels:
  • QA-F
  • ee-ts
  • liferay-fixpack-dxp-12-7110
• Branch Version/s:
  7.1.x
• Backported to Branch:
  Committed
• Fix Priority: 2
• Git Pull Request: https://github.com/brianchandotcom/liferay-portal/pull/71822

Steps to reproduce:

1. Start Liferay Portal
2. Control Panel > Content & Data > Web Content
3. Click "+" to add new folder
4. Give folder a name
5. Save the new folder
6. Repeat steps 3-5 and give folder same name
7. Banner will appear explaining the error. 

Results of Testing

 Expected:

A close button in the banner
 Actual:

no close button, just error message