fix: Change encoding for BitstringStatusList encodedList to multibase

[bstasyszyn]

BitstringStatusList encodedList is encoded as multibase base64url (with no padding).

[codecov]

Codecov Report

Attention: Patch coverage is 90.13158% with 15 lines in your changes missing coverage. Please review.

Project coverage is 84.87%. Comparing base (c0362a2) to head (5b70ee2).
Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
pkg/doc/vc/statustype/statusprocessor.go	85.07%	7 Missing and 3 partials ⚠️
...dentialstatus/eventhandler/eventhandler_service.go	57.14%	2 Missing and 1 partial ⚠️
pkg/internal/mock/status/status.go	50.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1800      +/-   ##
==========================================
+ Coverage   84.80%   84.87%   +0.06%     
==========================================
  Files         193      193              
  Lines       17635    17751     +116     
==========================================
+ Hits        14956    15066     +110     
- Misses       2141     2146       +5     
- Partials      538      539       +1     

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