Merge branch 'mo-fix-warning-csv' into 'master'

Fix warning deprecation

See merge request gitlab-org/gitlab!54370

lib/csv_builder.rb

@@ -16,6 +16,7 @@
 class CsvBuilder
   DEFAULT_ORDER_BY = 'id'.freeze
   DEFAULT_BATCH_SIZE = 1000
+  PREFIX_REGEX = /^[=\+\-@;]/.freeze
 
   attr_reader :rows_written
 
@@ -114,8 +115,8 @@ class CsvBuilder
 
   def excel_sanitize(line)
     return if line.nil?
+    return line unless line.is_a?(String) && line.match?(PREFIX_REGEX)
 
-    line = ["'", line].join if line =~ /^[=\+\-@;]/
-    line
+    ["'", line].join
   end
 end