feat(credentials)!: Account Update functions

[JR-Morgan]

V3 never updates the account credentials of accounts in the sqlite db
So user and server information remains stale.

I've fixed the functions in the SDK, and also added a way to upgrade only a single account (before you had to upgrade all accounts)
Not sure yet how/where we'll use these functions.

[codecov]

Codecov Report

❌ Patch coverage is 1.13636% with 87 lines in your changes missing coverage. Please review.
✅ Project coverage is 55.12%. Comparing base (00a6619) to head (e2429d4).

Files with missing lines	Patch %	Lines
src/Speckle.Sdk/Credentials/AccountManager.cs	2.12%	46 Missing ⚠️
...sts.Integration/Credentials/AccountManagerTests.cs	0.00%	36 Missing ⚠️
...sts.Integration/Credentials/AccountFactoryTests.cs	0.00%	5 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #435      +/-   ##
==========================================
- Coverage   64.14%   55.12%   -9.02%     
==========================================
  Files         289      330      +41     
  Lines       11835    13771    +1936     
  Branches     1137     1187      +50     
==========================================
  Hits         7591     7591              
- Misses       3928     5865    +1937     
+ Partials      316      315       -1     

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