Make capitalization of incident management objects uniform in modal

What does this MR do and why?

Swaps the capitalization of 'Project' to 'project' in the incident-management related modal for user deletion/removal.

Follow-up from: !73127 (comment 731065329)

Screenshots or screen recordings

How to set up and validate locally

1. Add a user to a project
2. Create an on-call schedule & add the user to it (Monitor > On-call schedules)
3. Create an escalation policy which routes directly the user
4. Go to Project information > Members & attempt to remove the user from the project. The modal should contain the updated strings.

Full detail: See !73127 (merged)

MR acceptance checklist

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