test: remove avro sqllogictest conflict marker

Author: getChan

datafusion/sqllogictest/test_files/avro.slt

@@ -285,7 +285,6 @@ SELECT id, string_col, int_col, bigint_col FROM alltypes_plain ORDER BY id LIMIT
 3 1 1 10
 4 0 0 0
 
-<<<<<<< HEAD
 # projection should follow column names even when external table column order differs
 query TB
 SELECT string_col, bool_col FROM alltypes_plain_reordered ORDER BY id LIMIT 2