feat: Add Blob as a default endowment

[FrederikBolding]

Add Blob as a default endowment for instanceof checks when using fetch.

https://consensyssoftware.atlassian.net/browse/WPC-1126

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 98.59%. Comparing base (58c5d8b) to head (00347d2).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #4063   +/-   ##
=======================================
  Coverage   98.59%   98.59%           
=======================================
  Files         425      425           
  Lines       12413    12414    +1     
  Branches     1969     1969           
=======================================
+ Hits        12238    12239    +1     
  Misses        175      175           

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