[ios] Replace all strong NSString* with copy

This CL replaces all strong NSStrings with a copy keyword. Also,
manually checked all updates and call the copy method if necessary.

for file in $(git grep -l "@property\(.*strong.*\) NSString" ./ios); do
  sed -i '' -e 's/\(@property(.*\), strong\(.*)\)\( NSString\)/\1, copy\2\3/' "$file"
  sed -i '' -e 's/\(@property(.*\)strong, \(.*)\)\(NSString\)/\1copy, \2\3/' "$file"
done

This CL was uploaded by git cl split.

R=vidhanj@google.com

Bug: 413648986
Change-Id: Ic7a5bf2b521c1c2fa0622159acf76c31d7970003
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6494450
Commit-Queue: Vidhan Jain <vidhanj@google.com>
Reviewed-by: Vidhan Jain <vidhanj@google.com>
Auto-Submit: Asami Doi <asamidoi@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1452605}