chore: make in-house openapi generators more reusable

[hamidzr]

Ticket

Description

Remove the dependency on determined package and BaseSession

https://hpe-aiatscale.slack.com/archives/C6D7MDSQ5/p1722972189991699

Test Plan

• check the diff in the generated code it should just show a set of

  -    session: "api.BaseSession",
  +    session: "RequestHandler",

Checklist

• Changes have been manually QA'd
• New features have been approved by the corresponding PM
• User-facing API changes have the "User-facing API Change" label
• Release notes have been added as a separate file under docs/release-notes/
  See Release Note for details.
• Licenses have been included for new code which was copied and/or modified from any external code

[netlify]

✅ Deploy Preview for determined-ui canceled.

Name	Link
🔨 Latest commit	b6d5153
🔍 Latest deploy log	https://app.netlify.com/sites/determined-ui/deploys/66bce1ffa3de78000857adc5

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 54.16%. Comparing base (f7e18fc) to head (b6d5153).
Report is 10 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #9806      +/-   ##
==========================================
- Coverage   54.27%   54.16%   -0.12%     
==========================================
  Files        1261      736     -525     
  Lines      155642   102646   -52996     
  Branches     3535     3534       -1     
==========================================
- Hits        84471    55594   -28877     
+ Misses      71033    46914   -24119     
  Partials      138      138              

Flag	Coverage Δ
backend	43.77% <ø> (-1.13%)	⬇️
harness	56.06% <ø> (-16.56%)	⬇️
web	53.71% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

see 656 files with indirect coverage changes