Fix FCM cannot be unsubscribed

[robertu7]

Firebase may throw below error while we call messaging.deleteToken(token):

A problem occured while unsubscribing the user from FCM: FirebaseError: Messaging: A problem occured while unsubscribing the user from FCM: Requested entity was not found. (messaging/token-unsubscribe-failed). (messaging/token-unsubscribe-failed).

Before Firebase fixes this bug, we catch this error, then continue to unsubscribe from local and server.

[codecov]

Codecov Report

Merging #865 into develop will not change coverage by %.
The diff coverage is n/a.

@@           Coverage Diff            @@
##           develop     #865   +/-   ##
========================================
  Coverage    90.00%   90.00%           
========================================
  Files            1        1           
  Lines           10       10           
  Branches         2        2           
========================================
  Hits             9        9           
  Misses           1        1           

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[robertu7]

(1) Web Push Notification 無法關閉 [1]

[guoliu]

LGTM 🌴

[devformatters]

Go. 🍍