[HotFix] Fix obbject extensions not written to extension_map.json

[the-praxs]

[HotFix] Fix obbject extensions not written to extension_map.json

1. Why?

   To properly write the obbject extensions in extension_map.json

2. What?

   • Adds property in ExtensionLoader and OpenBBGroups classes to access the entry points and groups respectively
   • Fixes the code in PackageBuilder class to properly write the obbject extensions in extension_map.json

3. Impact

   Severe impact since its a critical bug

4. Testing Done:

   Tested locally by building the static and validating the extension_map.json

5. Additional Notes:

   An additional PR will be created to release the updated openbb-core package