Ensures _auth_data_[provider] gets deleted from document

[flovilmart]

Before that PR, the auth_data{provider} would stay in the DB as = null, this proposed PR actually performs and $unset operation on the column to ensure a better consistency.

[flovilmart]

@Scoup if you could try this branch and let me know if the bug keeps occurring

[codecov-io]

Current coverage is 86.12%

Merging #1081 into master will increase coverage by +0.01% as of 03dec25

@@            master   #1081   diff @@
======================================
  Files           76      76       
  Stmts         5100    5103     +3
  Branches      1107    1108     +1
  Methods          0       0       
======================================
+ Hit           4392    4395     +3
  Partial         13      13       
  Missed         695     695       

Review entire Coverage Diff as of 03dec25

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