chore(node): fix kokoro build path for cloud-rad (#662)

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Source-Link: googleapis/synthtool@89d431f

packages/google-cloud-dialogflow/synth.metadata

@@ -4,7 +4,7 @@
       "git": {
         "name": ".",
         "remote": "https://github.com/googleapis/nodejs-dialogflow.git",
-        "sha": "ed10073ecf2c54d30ea2e14975dbef1ef974596f"
+        "sha": "8a7fbd32ddcc907538fd4b0b5a129054c082dc81"
       }
     },
     {
@@ -19,7 +19,7 @@
       "git": {
         "name": "synthtool",
         "remote": "https://github.com/googleapis/synthtool.git",
-        "sha": "3a00b7fea8c4c83eaff8eb207f530a2e3e8e1de3"
+        "sha": "89d431fb2975fc4e0ed24995a6e6dfc8ff4c24fa"
       }
     }
   ],