chore(main): release 2.56.4-SNAPSHOT (#3776)

🤖 I have created a release *beep* *boop*
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<details><summary>2.56.4-SNAPSHOT</summary>

### Updating meta-information for bleeding-edge SNAPSHOT release.
</details>

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Author: release-please[bot]

java-iam/pom.xml

@@ -145,12 +145,12 @@
       <dependency>
         <groupId>com.google.api.grpc.api.grpc</groupId>
         <artifactId>proto-google-iam-v3</artifactId>
-        <version>1.50.3</version><!-- {x-version-update:proto-google-iam-v3:current} -->
+        <version>1.50.4-SNAPSHOT</version><!-- {x-version-update:proto-google-iam-v3:current} -->
       </dependency>
       <dependency>
         <groupId>com.google.api.grpc.api.grpc</groupId>
         <artifactId>grpc-google-iam-v3</artifactId>
-        <version>1.50.3</version><!-- {x-version-update:grpc-google-iam-v3:current} -->
+        <version>1.50.4-SNAPSHOT</version><!-- {x-version-update:grpc-google-iam-v3:current} -->
       </dependency>
       <dependency>
         <groupId>javax.annotation</groupId>