fix: replace assert statements with explicit raise in ASR models

[stanley1208]

What does this PR do?

Replace 5 assert statements with explicit raise ValueError/raise RuntimeError across 4 ASR files, per the Contributor guidelines which state:

"RaiseError is preferred to assert"

This is a follow-up to #15444 which applied the same fix to aed_multitask_models.py.

Changes:

• hybrid_rnnt_ctc_models.py:342 — Validate decoder_type and ctc_decoder attribute
• sortformer_diar_models.py:470 — Validate batch size consistency after signal processing
• msdd_models.py:459 — Validate gradient detachment of ms_avg_embs
• msdd_models.py:750 — Validate scale mapping dimensions match
• manifest_utils.py:338 — Validate data path count matches expected count

Collection: ASR

Changelog

• Replace 5 assert statements with raise ValueError/raise RuntimeError across 4 ASR files

Before your PR is "Ready for review"

• Make sure you read and followed Contributor guidelines
• Did you write any new necessary tests? (N/A — no behavior change)
• Did you add or update any necessary documentation?

PR Type:

• Bugfix

[stanley1208]

@nithinraok Ready for review — follow-up to #15444, replaces 5 more assert statements across 4 ASR files per CONTRIBUTING.md guidelines. Thanks!