As a CRM user viewing an email in a shared queue or my activities, I need an ability to report the email as a phishing email.

There is an article of Microsoft that mentions a report phishing email adds - on: Enable the Report Message or the Report Phishing add-ins - Microsoft Defender for Office 365 | Microsoft Learn 

However, this add-on is applied only to a button on Outlook and currently CRM does not have that feature. This information is confirmed in article: How do I report a suspicious email or file to Microsoft?