tests: add dbus monitor log to interfaces-accounts-service

[mvo5]

We saw some failures in the tests:

Creating account
+ gdbus call --session --timeout 300 --dest=org.gnome.OnlineAccounts --object-path=/org/gnome/OnlineAccounts/Manager --method=org.gnome.OnlineAccounts.Manager.AddAccount imap_smtp test@example.com 'Display Name' '{}' '{'\''Enabled'\'': '\''true'\'', '\''EmailAddress'\'': '\''test@example.com'\'', '\''Name'\'': '\''Test User'\'', '\''ImapHost'\'': '\''imap.example.com'\'', '\''SmtpHost'\'': '\''mail.example.com'\''}'
Error: GDBus.Error:org.freedesktop.DBus.Error.InvalidArgs: Type of message, '(ssssa{ss})', does not match expected type '(sssa{sv}a{ss})'

and it would be nice to get to the bottom of this.

[codecov-io]

Codecov Report

Merging #5602 into master will increase coverage by <.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #5602      +/-   ##
==========================================
+ Coverage   78.94%   78.94%   +<.01%     
==========================================
  Files         518      518              
  Lines       39439    39439              
==========================================
+ Hits        31134    31136       +2     
+ Misses       5773     5772       -1     
+ Partials     2532     2531       -1

Impacted Files	Coverage Δ
overlord/hookstate/hookmgr.go	74.51% <0%> (+0.96%)	⬆️

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