Pin docker.elastic.co/wolfi/chainguard-base-fips Docker tag to ebfc3f1 (#126065)

This PR contains the following updates:

| Package | Update | Change | |---|---|---| |
docker.elastic.co/wolfi/chainguard-base-fips | pinDigest |  -> `ebfc3f1`
|

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build-tools-internal/src/main/java/org/elasticsearch/gradle/internal/DockerBase.java

@@ -26,7 +26,7 @@ public enum DockerBase {
         "-wolfi",
         "apk"
     ),
-    FIPS("docker.elastic.co/wolfi/chainguard-base-fips:sha256-ebfc3f1d7dba992231747a2e05ad1b859843e81b5e676ad342859d7cf9e425a7", "-fips", "apk"),
+    FIPS("docker.elastic.co/wolfi/chainguard-base-fips:sha256-ebfc3f1d7dba992231747a2e05ad1b859843e81b5e676ad342859d7cf9e425a7@sha256:ebfc3f1d7dba992231747a2e05ad1b859843e81b5e676ad342859d7cf9e425a7", "-fips", "apk"),
     // spotless:on
     // Based on WOLFI above, with more extras. We don't set a base image because
     // we programmatically extend from the wolfi image.