[BugFix] etf.sectors(provider='tmx') - Fix Key Error When No Info Found

[deeleeramone]

1. Why?:

   • KeyError caused by empty result.
   • Found a widget columnDef being defined as a date when it is a percent.

2. What?:

   • Fixes KeyError
   • Narrows scope of date-like field type definitions by openbb-platform-api

3. Impact:

   • Fixes bugs and improves accuracy.

4. Testing Done:

   • You can check with:

     • `obb.etf.sectors("CASH", provider="tmx")
     • `obb.etf.info("CASH", provider="tmx")

   • Workspace backend widget, "Return YTD", was missing from a bar chart created by etf.info

     • etf.sectors was not returning None cleanly.