Stop building read-the-docs for flyteidl

[eapolinario]

Tracking issue

NA

Why are the changes needed?

We no longer build the read-the-docs flyteidl site separately. That's handled by the monodocs build. We keep getting alerts due to old dependencies in the flyteidl docs requirements files.

What changes were proposed in this pull request?

This PR removes the mentions to doc-requirements.txt in flyteidl.

How was this patch tested?

Setup process

Screenshots

Check all the applicable boxes

• I updated the documentation accordingly.
• All new and existing tests passed.
• All commits are signed-off.

Related PRs

Docs link

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 59.00%. Comparing base (cb6384a) to head (10e749c).
Report is 6 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #5120      +/-   ##
==========================================
+ Coverage   58.49%   59.00%   +0.50%     
==========================================
  Files         627      645      +18     
  Lines       54155    55672    +1517     
==========================================
+ Hits        31680    32850    +1170     
- Misses      19942    20226     +284     
- Partials     2533     2596      +63     

Flag	Coverage Δ
unittests	59.00% <ø> (+0.50%)	⬆️

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