fix: Implemented nested logicalType check

[bengels97]

Original issue described in: #726

Included a logicalType key check in BaseGenerator.parse_logical_type that does not break any of the existing model generations. But does enable the generation of a model for a schema with logicalType and type not defined under a type key (as described in the issue).

Note that my linter has updated some of the indentations in the code.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 99.48%. Comparing base (a2239b2) to head (00b2564).
Report is 1 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #734   +/-   ##
=======================================
  Coverage   99.48%   99.48%           
=======================================
  Files          34       34           
  Lines        1947     1947           
=======================================
  Hits         1937     1937           
  Misses         10       10           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.