[Offline Mode] Fix Config file deletion, RTC initialization failure

[brentru]

Resolves: #735

This pull request:

• Improved error handling in Wippersnapper_FS::CreateFileConfig by raising an error if config.json cannot be deserialized, instead of silently removing it. (src/provisioning/tinyusb/Wippersnapper_FS.cpp)
• Ensured proper cleanup of the old config.json file before writing a new one in Wippersnapper_FS::WriteFileConfig. This prevents potential conflicts or corruption. (src/provisioning/tinyusb/Wippersnapper_FS.cpp)
• Uses the proper I2C bus when initializing the RTC chip by getting a ptr to the bus from the controller rather than assuming a default.

[github-actions]

Test Results

6 tests  ±0   6 ✅ ±0   41s ⏱️ -1s
1 suites ±0   0 💤 ±0 
1 files   ±0   0 ❌ ±0 

Results for commit 11e2116. ± Comparison against base commit 5564777.