[backend] Fix for persona_name global search and entity filter/link registration

[ParamConstructor]

Bugfix PR - Searching for a Persona Observable. Filtering on Entity=Persona or performing a search on a Persona returns 0 results.

Issue #9063 Submitted for this bug

Proposed changes

• Added persona_name field to engine search fields - Fixed Global Search
• Added missed stixCyberObservable-registrationRef to support filter

Related issues

• N/A

Checklist

• [X] I consider the submitted work as finished
• [X] I tested the code for its functionality
• [X] - N/A - I wrote test cases for the relevant uses case (coverage and e2e)
• [X] - N/A - I added/update the relevant documentation (either on github or on notion)
• [X] Where necessary I refactored code to improve the overall quality

Further comments

[codecov[bot]]

Codecov Report

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

Project coverage is 64.69%. Comparing base (5f4ff09) to head (d6c8af0). Report is 10 commits behind head on master.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #9064 +/- ## ======================================= Coverage 64.68% 64.69% ======================================= Files 620 620 Lines 59208 59210 +2 Branches 6520 6520 ======================================= + Hits 38301 38303 +2 Misses 20907 20907 ```

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