fix: project and engagement names should not have to be unique (resolves #2140)

[jobara]

Resolves #2140

• Removes requirements for Project and Engagement names to be unique.

Prerequisites

If this PR changes PHP code or dependencies:

• [x] I've run composer format and fixed any code formatting issues.
• [x] I've run composer analyze and addressed any static analysis issues.
• [x] I've run php artisan test and ensured that all tests pass.
• [x] I've run composer localize to update localization source files and committed any changes.

If this PR changes CSS or JavaScript code or dependencies:

• [ ] I've run npm run lint and fixed any linting issues.
• [ ] I've run npm run build and ensured that CSS and JavaScript assets can be compiled.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Comparison is base (c585c7a) 97.94% compared to head (3f226e7) 97.93%. Report is 1 commits behind head on dev.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## dev #2141 +/- ## ============================================ - Coverage 97.94% 97.93% -0.01% Complexity 2146 2146 ============================================ Files 333 333 Lines 9812 9804 -8 ============================================ - Hits 9610 9602 -8 Misses 202 202 ```

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