Fix indexing in convolve1d with mode="same"

[tvwenger]

Description

Fixes indexing issue introduced in convolve1d.

Related Issue

• Closes BUG: convolve1d mode="same" indexing error #1336
• Related to Implement batched convolve1d #1318
• Related to Convolve1d rewrites #1319

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):

---

📚 Documentation preview 📚: https://pytensor--1337.org.readthedocs.build/en/1337/

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 82.01%. Comparing base (3af923b) to head (398e038).
Report is 3 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1337   +/-   ##
=======================================
  Coverage   82.01%   82.01%           
=======================================
  Files         203      203           
  Lines       48805    48805           
  Branches     8688     8688           
=======================================
  Hits        40026    40026           
  Misses       6627     6627           
  Partials     2152     2152           

Files with missing lines	Coverage Δ
pytensor/tensor/signal/conv.py	97.05% <100.00%> (ø)

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[ricardoV94]

Thanks 🙏, good catch