HPCC-12339 Change user's filter for logical file name to lower case

In WsDFU.DFUQuery, a user may type in a logical file name or a
prefix as a filter. Upper case value inside the filter should be
changed to lower case before using as the filter of the DFUQuery.

Signed-off-by: wangkx <kevin.wang@lexisnexis.com>

esp/services/ws_dfu/ws_dfuService.cpp

@@ -3056,6 +3056,7 @@ void CWsDfuEx::setFileNameFilter(const char* fname, const char* prefix, StringBu
         }
         fileNameFilter.append("*");
     }
+    fileNameFilter.toLowerCase();
     filterBuf.append(DFUQFTspecial).append(DFUQFilterSeparator).append(DFUQSFFileNameWithPrefix).append(DFUQFilterSeparator).append(fileNameFilter.str()).append(DFUQFilterSeparator);
 }