[Java][resttemplate] Add test for bearer auth (#17081)

* add bearer auth API to echo-api

* run generate-samples.sh

* add resttemplate echo-api sample

* add bearer auth test

* remove @Ignore

samples/client/echo_api/java/feign-gson/api/openapi.yaml

@@ -551,6 +551,23 @@ paths:
       tags:
       - auth
       x-accepts: text/plain
+  /auth/http/bearer:
+    post:
+      description: To test HTTP bearer authentication
+      operationId: test/auth/http/bearer
+      responses:
+        "200":
+          content:
+            text/plain:
+              schema:
+                type: string
+          description: Successful operation
+      security:
+      - http_bearer_auth: []
+      summary: To test HTTP bearer authentication
+      tags:
+      - auth
+      x-accepts: text/plain
 components:
   requestBodies:
     Pet:
@@ -822,4 +839,7 @@ components:
     http_auth:
       scheme: basic
       type: http
+    http_bearer_auth:
+      scheme: bearer
+      type: http