Remove linux/arm/v7 from multi-arch Docker image

[pkosiec]

This is caused by this bug: nodejs/node#50847
Until it is resolved, the Mongo Seeding multi-arch image won't be built armv7platform, unfortunately.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (26d4573) 91.27% compared to head (b2dec26) 91.27%.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #218   +/-   ##
=======================================
  Coverage   91.27%   91.27%           
=======================================
  Files          17       17           
  Lines         298      298           
  Branches       62       62           
=======================================
  Hits          272      272           
  Misses         17       17           
  Partials        9        9           

Flag	Coverage Δ
cli	93.75% <ø> (ø)
core	90.59% <ø> (ø)

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