fix(enum): strip FlagsArray from project defaults for non-[Flags] enums (#344)

* fix(enum): strip FlagsArray from project defaults for non-[Flags] enums

When FlagsArray is set via project-level AVI_EJC_DefaultEnumSerializationStrategy,
it should only apply to enums with [Flags] attribute. Non-flags enums now silently
get FlagsArray stripped from their strategies instead of generating a warning.

The AVI_EJC_0003 warning is now only emitted when FlagsArray is explicitly set
per-enum via [EnumJsonConverter] on a non-[Flags] enum.

Add ProjectConfigurationWorks_FlagsArray snapshot test verifying both behaviors.

Co-Authored-By: Claude <noreply@anthropic.com>

* Drop framework specific snapshots

* fix(enum): fall back to FirstEnumName when FlagsArray-only default is stripped

When AVI_EJC_DefaultEnumSerializationStrategy is configured as just 'FlagsArray'
(without FirstEnumName or BackingType), stripping FlagsArray for non-[Flags] enums
left serializationStrategies empty, producing broken 'SerializationStrategy => ;'
in the generated converter.

Now falls back to FirstEnumName when stripping leaves no strategies.
Add ProjectConfigurationWorks_FlagsArrayOnly snapshot test covering this edge case.

Co-Authored-By: Claude <noreply@anthropic.com>

* Drop framework specific snapshots

* Minor typo

---------

Co-authored-by: Claude <noreply@anthropic.com>

Author: trejjam