Numba AdvancedIndexing: Complete support for integer advanced indexing

[ricardoV94]

(and mixed basic indexing)

This covers the cases with default ignore_updates=False for inc_subtensor,

Boolean indices are converted to integer indices during specialize rewriting.

This was motivated by #811 where it found the logic for when object fallback was needed was wrong.
Fixing it, revealed we had less cases covered by pure numba than thought, hence this PR.

[Copilot]

Pull request overview

This PR completes support for integer advanced indexing in PyTensor's Numba backend by implementing a comprehensive dispatch mechanism that handles all forms of advanced indexing with basic and vector integer indices, including non-consecutive indices and mixed basic/advanced indexing patterns.

Key Changes:

• Replaces specialized multidimensional bool/int index raveling rewrites with a simpler bool_idx_to_nonzero rewrite that converts boolean indices to integer indices via nonzero()
• Implements a new codegen-based vector_integer_advanced_indexing dispatcher that generates custom Numba functions for each indexing pattern, eliminating most object mode fallbacks
• Updates tests to remove the objmode_needed parameter and consolidates test parameters for ignore_duplicates behavior

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 7 comments.

File	Description
tests/link/numba/test_subtensor.py	Removes objmode_needed parameter from tests and consolidates duplicate index test parameters, reflecting that most indexing operations no longer require object mode fallback
pytensor/tensor/rewriting/subtensor.py	Simplifies boolean indexing rewrite by converting to nonzero() instead of raveling, and removes complex multidimensional integer indexing rewrites that are now handled by the dispatcher
pytensor/link/numba/dispatch/subtensor.py	Implements comprehensive codegen-based dispatcher for advanced indexing that handles transpose operations, broadcasting, and index raveling at runtime without requiring object mode