Fix RecoverySourceHandlerTests (#79995)

Today RecoverySourceHandlerTests#generateFiles can generate files with
different name but same content since the lengths that we use for tests
are small. In order to avoid tripping assertions when we check that two
files are different we should check that the name is different as well
as the content are different.

Closes #79502
Backport of #79546

Author: fcofdez

server/src/test/java/org/elasticsearch/indices/recovery/RecoverySourceHandlerTests.java

@@ -1653,7 +1653,7 @@ private boolean containsSnapshotFile(
     }
 
     private boolean containsFile(List<StoreFileMetadata> filesMetadata, StoreFileMetadata storeFileMetadata) {
-        return filesMetadata.stream().anyMatch(f -> f.isSame(storeFileMetadata));
+        return filesMetadata.stream().anyMatch(f -> f.name().equals(storeFileMetadata.name()) && f.isSame(storeFileMetadata));
     }
 
     private boolean containsFile(List<StoreFileMetadata> files, String fileName, long length) {