[RNE Rewrite] refactor(cpp): cleanup core and extension error handling and formatting

[barhanc]

Description

• Removes dead code and fix formatting in core (dtype, schema, tensor, tensor_helpers)
• Fixes exception shadowing in extension ops (cv, math, nlp, speech)
• Normalizes error propagation and prefixes across C++ extensions

Introduces a breaking change?

• Yes
• No

Type of change

• Bug fix (change which fixes an issue)
• New feature (change which adds functionality)
• Documentation update (improves or adds clarity to existing documentation)
• Other (chores, tests, code style improvements etc.)

Tested on

• iOS
• Android

Testing instructions

N/A

Screenshots

Related issues

Checklist

• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have updated the documentation accordingly
• My changes generate no new warnings

Additional notes

[msluszniak]

Just one small comment, but other than that it is 👌🏻