Fix testing/submitting YAML

Partially revert !1434 (merged) and reimplement the quality of life improvements requested in lhcb-dpa/prod-requests#10 (closed)

BEGINRELEASENOTES

*ProductionManagement
NEW: Add test for MC request YAML
NEW: Support shorthand for specifying production request filetype visibility
FIX: Add more default values in ProductionManagement pydantic Models
NEW: Get ProductionBase.author from current proxy if it isn't set already
NEW: Make DataProduction.input_dataset.conditions_id optional
NEW: Enhance schema for DataProduction.input_dataset.conditions_dict

ENDRELEASENOTES