[BugFix] FMP Key Metrics

[deeleeramone]

1. Why?:

   • Fixes issues using with_ttm parameter.
   • Fixes field name aliases - we actually need both __alias_dict__ and alias in the Field definition.

2. What?:

   • General model clean-up.
   • Identify more fields that are % values, and add json_schema_extra to the Field definition.

3. Impact:

   • Expands a few field names to be more verbose.
     • roe -> return_on_equity

4. Testing Done:

   • Multiple symbols
   • quarter and annual, with_ttm True/False