fix: Fix description of an interpreter field, validate if the field i…

…s not unspecified (#604)

* fix: Fix description of an interpreter field, validate if the field is not unspecified

PiperOrigin-RevId: 427987153

Source-Link: googleapis/googleapis@a1b62c1

Source-Link: googleapis/googleapis-gen@bda7567
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packages/google-cloud-asset/protos/google/cloud/osconfig/v1/os_policy.proto

@@ -354,7 +354,7 @@ message OSPolicy {
       message Exec {
         // The interpreter to use.
         enum Interpreter {
-          // Defaults to NONE.
+          // Invalid value, the request will return validation error.
           INTERPRETER_UNSPECIFIED = 0;
 
           // If an interpreter is not specified, the