Corrects tether signal okay string to match the id

Looks like there was a copy paste error with
IDS_ONC_TETHER_SIGNAL_STRENGTH_OKAY having the string "Weak" which was
incorrect

Change-Id: Ic0dbadc4fb34074a3fc633c2103e54bc7441abd9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1939686
Auto-Submit: James Vecore <vecore@google.com>
Commit-Queue: Kyle Horimoto <khorimoto@chromium.org>
Reviewed-by: Kyle Horimoto <khorimoto@chromium.org>
Cr-Commit-Position: refs/heads/master@{#721273}

chrome/app/settings_strings.grdp

@@ -2723,7 +2723,7 @@
       Weak
     </message>
     <message name="IDS_ONC_TETHER_SIGNAL_STRENGTH_OKAY" desc="Settings > Internet > Label used to describe the signal strength of a device's cellular connection when the signal is okay. The strength value is 2 on a scale from 1 (min) to 5 (max).">
-      Weak
+      Okay
     </message>
     <message name="IDS_ONC_TETHER_SIGNAL_STRENGTH_GOOD" desc="Settings > Internet > Label used to describe the signal strength of a device's cellular connection when the signal is good. The strength value is 3 on a scale from 1 (min) to 5 (max).">
       Fine