fix(gconv): prevent panic when binding array type (uuid.UUID) parameters (#4786)

[waterWang]

Fixes #4786

Problem

reflect.Value.IsNil panics when called on an array value. uuid.UUID is [16]byte (a fixed-size array), so when a struct field like:

type XXXReq struct {
   IDs []uuid.UUID \`json:"ids"\`
}

is bound via HTTP request, the converter enters the reflect.Slice/Array/Pointer/Interface case and calls IsNil on the array element, causing a panic:

reflect: call of reflect.Value.IsNil on array Value

Fix

Skip the IsNil check when the reflect.Kind is reflect.Array, since arrays can never be nil in Go.

Verification

• reflect.Array values are never nil, so the IsNil() guard is unnecessary for arrays
• The ISet interface check is still reached for array types that implement it (though no standard library array type does)
• All existing behavior for slices, pointers, and interfaces is unchanged