Added Vector Store File List properties that allow for pagination

[MattDavisRV]

Describe the change

This change adds pagniation properties for listing Vector Store Files. A vector store can handle up to 10,000 files at the time of this PR and a max of 100 files can be returned per request.

Provide OpenAI documentation link

It's not specifically outlined in the documentation, however, the example response has these fields listed.

https://platform.openai.com/docs/api-reference/vector-stores-files/listFiles

Describe your solution

Added the missing properties that are returned from the API request.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 98.86%. Comparing base (774fc9d) to head (008f597).
Report is 68 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #891      +/-   ##
==========================================
+ Coverage   98.46%   98.86%   +0.40%     
==========================================
  Files          24       26       +2     
  Lines        1364     1761     +397     
==========================================
+ Hits         1343     1741     +398     
+ Misses         15       14       -1     
  Partials        6        6              

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