Hi itn telephone

[mayuris-00]

What does this PR do ?

Adds IP address support to the Hindi ITN telephone class, following the English ITN pattern (IP handled in telephone). Includes TSV-driven डॉट mapping, octet repetition via closure, and telephone test coverage for IPs.

Note: graph_utils.py, data/electronic/symbols.tsv, and the Jenkinsfile cache bump are byte-identical to #437 (this PR depends on those shared helpers). Once #437 merges, those files drop out of this diff automatically, leaving telephone-only changes.

All Hindi ITN/TN pytests pass locally (1027/1027).

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Pre checks:

• Have you signed your commits? Use git commit -s to sign.
• Do all unittests finish successfully before sending PR?
  1. pytest or (if your machine does not have GPU) pytest --cpu from the root folder (given you marked your test cases accordingly @pytest.mark.run_only_on('CPU')).
  2. Sparrowhawk tests bash tools/text_processing_deployment/export_grammars.sh --MODE=test ...
• If you are adding a new feature: Have you added test cases for both pytest and Sparrowhawk here.
• Have you added __init__.py for every folder and subfolder, including data folder which has .TSV files?
• Have you followed codeQL results and removed unused variables and imports (report is at the bottom of the PR in github review box) ?
• Have you added the correct license header Copyright (c) 2023, NVIDIA CORPORATION & AFFILIATES. All rights reserved. to all newly added Python files?
• If you copied nemo_text_processing/text_normalization/en/graph_utils.py your header's second line should be Copyright 2015 and onwards Google, Inc.. See an example here.
• Remove import guards (try import: ... except: ...) if not already done.
• If you added a new language or a new feature please update the NeMo documentation (lives in different repo).
• Have you added your language support to tools/text_processing_deployment/pynini_export.py.

PR Type:

• New Feature
• Bugfix
• Documentation
• Test

If you haven't finished some of the above items you can still open "Draft" PR.