Fix E721: do not compare types, for exact checks use is / is not

[maresb]

Description

This splits out a controvertial part of #581 code cleanup. See #581 (comment).

This runs a risk of breaking something extremely subtle, so I think we will not want to merge this, but I wanted to at least give this its own PR number for reference.

Checklist

• Checked that the pre-commit linting/style checks pass
• Included tests that prove the fix is effective or that the new feature works
• Added necessary documentation (docstrings and/or example notebooks)
• If you are a pro: each commit corresponds to a relevant logical change

Type of change

• New feature / enhancement
• Bug fix
• Documentation
• Maintenance
• Other (please specify):

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 84.61538% with 4 lines in your changes missing coverage. Please review.

Project coverage is 80.83%. Comparing base (4b6a444) to head (e4d207b).
Report is 170 commits behind head on main.

Files with missing lines	Patch %	Lines
pytensor/graph/null_type.py	0.00%	1 Missing ⚠️
pytensor/raise_op.py	50.00%	1 Missing ⚠️
pytensor/scalar/basic.py	50.00%	1 Missing ⚠️
pytensor/tensor/rewriting/math.py	0.00%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #596   +/-   ##
=======================================
  Coverage   80.83%   80.83%           
=======================================
  Files         163      163           
  Lines       46897    46897           
  Branches    11468    11468           
=======================================
  Hits        37910    37910           
  Misses       6774     6774           
  Partials     2213     2213           

Files with missing lines	Coverage Δ
pytensor/compile/debugmode.py	61.33% <100.00%> (ø)
pytensor/compile/ops.py	83.57% <100.00%> (ø)
pytensor/graph/basic.py	88.61% <ø> (ø)
pytensor/graph/rewriting/unify.py	99.33% <100.00%> (ø)
pytensor/ifelse.py	51.70% <100.00%> (ø)
pytensor/link/c/params_type.py	80.41% <ø> (ø)
pytensor/link/c/type.py	75.98% <ø> (ø)
pytensor/scalar/math.py	87.34% <100.00%> (ø)
pytensor/scan/op.py	84.71% <100.00%> (ø)
pytensor/sparse/basic.py	82.53% <ø> (ø)
... and 9 more

[ricardoV94]

I think we can go ahead with this one @maresb

Can you rebase?

[maresb]

@ricardoV94, rebase is complete.

[ricardoV94]

@maresb were we suppressing this pre-commit rule, should we reactivate it?

[maresb]

@maresb were we suppressing this pre-commit rule, should we reactivate it?

No we weren't, it's just totally broken in Ruff: astral-sh/ruff#6465

But now E721 passes with flake8