fix: error handling for invalid gRPC endpoints

[technicallyty]

some hand holding for common error of using http for grpc endpoints

also reformatting a switch case that bothered me

[codecov]

Codecov Report

Attention: Patch coverage is 68.42105% with 6 lines in your changes missing coverage. Please review.

Project coverage is 56.99%. Comparing base (4afa6c6) to head (ad58f67).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
cmd/connect/main.go	73.33%	4 Missing ⚠️
providers/factories/oracle/marketmap.go	50.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #757      +/-   ##
==========================================
+ Coverage   55.56%   56.99%   +1.42%     
==========================================
  Files         208      208              
  Lines       11615    11630      +15     
==========================================
+ Hits         6454     6628     +174     
+ Misses       4558     4398     -160     
- Partials      603      604       +1     

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