Change autoapi_ignore to fix rtd

[freddyaboulton]

Pull Request Description

Currently, RTD latest is breaking - https://readthedocs.com/projects/feature-labs-inc-evalml/builds/681063/

The problem is that I told autoapi to ignore test files with *test* but the problem is that RTD checks our code into a directory called latest so *test* ignores everything 🙈

I changed it so that only files in evalml/tests are ignored now.

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After creating the pull request: in order to pass the release_notes_updated check you will need to update the "Future Release" section of docs/source/release_notes.rst to include this pull request by adding :pr:123.

[codecov]

Codecov Report

Merging #2530 (9db8be1) into main (ce4a687) will not change coverage.
The diff coverage is n/a.

@@          Coverage Diff          @@
##            main   #2530   +/-   ##
=====================================
  Coverage   99.7%   99.7%           
=====================================
  Files        283     283           
  Lines      25903   25903           
=====================================
  Hits       25802   25802           
  Misses       101     101           

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