Fix: Add error handling if config is missing (#2279)

[Vanshikagup2206]

IMPORTANT: Where possible all PRs must be linked to a Github issue

Summary
This PR adds error handling for missing configuration files in the configuration loading process.
If a configuration file is missing, the code now logs an error and calls configsLoadedCallback(false) without crashing the app.

Changes Made

• Added a try-catch block to handle FileNotFoundException during configuration loading.
• Logged a clear error message when configuration is missing.
• Ensured the callback is safely invoked to prevent app crashes.

Fixes #2279

Engineer Checklist

• I have written unit tests for any new feature(s) or bug fixes (Verified manually in this case)
• I have added any strings visible on UI components to the strings.xml file (Not Applicable)
• I have updated the CHANGELOG.md file for any notable changes to the codebase (N/A for now)
• I have run ./gradlew spotlessApply and ./gradlew spotlessCheck to check my code follows the project's style guide
• I have built and run the FHIRCore app to verify my change fixes the issue and/or does not break the app
• I have checked that this PR does NOT introduce breaking changes