Updates for clean build with latest ESP-IDF v5.4

[DakshitBabbar]

Description

Context:
The CI checks for this Repository requires that the code is built without errors with the latest version of ESP-IDF (v5.4) along with other versions. It happens to be that a number of warnings that were suppressed in the previous ESP-IDF versions are now treated as errors and the build fails for it. Hence this PR updates the relevant code to build it without any warnings or errors with the latest ESP-IDF v5.4.

This PR:

• Removes the definitions of unused functions.
• Removes the instances of constness related warnings
• Updates the esp-aws-iot submodule pointed to the updated code that builds with the latest ESP-IDF v5.4

Test Steps

The code is building successfully with the latest ESP-IDF v5.4

Checklist:

• I have tested my changes. No regression in existing tests.
• I have modified and/or added unit-tests to cover the code changes in this Pull Request.

Related Issue

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