fix: Remove undefined params in MultichainRouter

[FrederikBolding]

The MultichainRouter incorrectly passes on params that could be undefined, this PR fixes that.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 98.07%. Comparing base (ee0c1f3) to head (38f1ddf).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #3388   +/-   ##
=======================================
  Coverage   98.07%   98.07%           
=======================================
  Files         398      398           
  Lines       10966    10967    +1     
  Branches     1724     1725    +1     
=======================================
+ Hits        10755    10756    +1     
  Misses        211      211           

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[GuillaumeRx]

Nit: Could we have a test to ensure we don't pass undefined ?

[FrederikBolding]

Nit: Could we have a test to ensure we don't pass undefined ?

Added an assertion to an existing test!