Fix form/explode=false incorrectly splitting primitive string values on commas

[f-kanari]

Summary

BindQueryParameterWithOptions and BindRawQueryParameter unconditionally split query parameter values on commas when explode=false, even for primitive (non-array, non-object) destination types. This causes
parameters like scope=openid,profile,email to fail with:

Invalid format for parameter scope: multiple values for single value parameter 'scope'

Per the OpenAPI specification, explode has no effect on primitive types — the serialization is identical regardless of the explode value:

Type	explode=true	explode=false
primitive	id=5	id=5
array	id=3&id=4&id=5	id=3,4,5
object	role=admin&firstName=Alex	role,admin,firstName,Alex

Comma splitting is only meaningful for array and object types.

Changes

• bindparam.go: In both BindQueryParameterWithOptions and BindRawQueryParameter, check the destination type before splitting on commas. For primitive types (reflect.Kind is not Slice, Struct, or
  Map), bind the raw value directly without splitting.

How it was tested

• Added regression tests for BindQueryParameter with form/explode=false binding a comma-containing string (required and optional variants)
• Added regression tests for BindRawQueryParameter with form/explode=false binding a percent-encoded comma-containing string (required and optional variants)
• All existing tests continue to pass

Related

This is similar in spirit to #115 / #114, which fixed the same class of bug in BindStyledParameterWithOptions for simple/form style parameters. This PR addresses the equivalent issue in the query parameter
binding functions.