Avoid duplicating RegEx in .strings lint via better sed usage

Hat tip @AliSoftware.

See
#19553 (comment)

Author: mokagio

.buildkite/commands/lint-localized-strings-format.sh

@@ -29,8 +29,8 @@ if [[ $EXIT_CODE -ne 0 ]]; then
   #
   # Notice the second `sed` call that removes the ANSI escape sequences that
   # Fastlane uses to color the output.
-  grep -e "\[.*\].*genstrings:" $LOGS \
-    | sed -e 's/\[.*\].*genstrings: error: /- /' \
+  cat $LOGS \
+    | sed -ne 's/\[.*\].*genstrings: error: /- /p' \
     | sed -e $'s/\x1b\[[0-9;]*m//g' \
     | sort \
     | uniq \