feat: creates a modal to add members

[katrinan029]

Description

Creates a modal to add members to an existing group
https://2u-internal.atlassian.net/browse/ENT-9602

For all changes

• Ensure adequate tests are in place (or reviewed existing tests cover changes)

Only if submitting a visual change

• Ensure to attach screenshots
• Ensure to have UX team confirm screenshots

[codecov]

Codecov Report

Attention: Patch coverage is 57.69231% with 66 lines in your changes missing coverage. Please review.

Project coverage is 85.37%. Comparing base (371f043) to head (368dfe2).

Files with missing lines	Patch %	Lines
...onents/PeopleManagement/AddMembersModalContent.jsx	5.26%	36 Missing ⚠️
...rc/components/PeopleManagement/AddMembersModal.jsx	55.26%	17 Missing ⚠️
...ement/data/hooks/useEnterpriseLearnersTableData.js	0.00%	5 Missing ⚠️
src/data/services/LmsApiService.js	20.00%	4 Missing ⚠️
...mponents/PeopleManagement/AddMembersBulkAction.jsx	84.61%	2 Missing ⚠️
...nents/PeopleManagement/RemoveMembersBulkAction.jsx	88.88%	1 Missing ⚠️
...gement/data/hooks/useAllEnterpriseGroupLearners.js	92.30%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1363      +/-   ##
==========================================
- Coverage   85.72%   85.37%   -0.35%     
==========================================
  Files         609      617       +8     
  Lines       13363    13474     +111     
  Branches     2812     2780      -32     
==========================================
+ Hits        11455    11504      +49     
- Misses       1838     1900      +62     
  Partials       70       70              

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