Add workaround for old buildx version

[pauldowman]

Description

#18879 introduced major changes to building prestates, and fixed some CI issues that hadn't been tackled yet witht the kona import to the monorepo. It broke some things that can't easily be found locally.

This is claude's fix for this unknown flag: --allow error in CI.

It looks like docker buildx in this repo's CI may be an old version that doesn't support the --allow flag. The kona prestate build config that was recently imported into the monorepo uses it. This is a workaround. (Claude is pretty sure that older versions which don't support --allow will still work because on older versions filesystem access was allowed by default, so omitting the flag should work correctly. This is hard to test locally so we'll see.

This PR also reverts a workaround that made devstack prefer ws:// connections because HTTP wasn't working properly with supernode. It's safe to revert because supernode now supports HTTP polling.

This is probably not the last build fix for this set of changes since the only way to test is in CI.

Tests

Additional context

Metadata

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 76.8%. Comparing base (00b1c81) to head (86f1f93).
⚠️ Report is 1 commits behind head on develop.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop   #19031      +/-   ##
===========================================
+ Coverage     73.0%    76.8%    +3.7%     
===========================================
  Files          188      383     +195     
  Lines        10943    42840   +31897     
===========================================
+ Hits          7993    32902   +24909     
- Misses        2804     9938    +7134     
+ Partials       146        0     -146     

Flag	Coverage Δ
cannon-go-tests-64	?
contracts-bedrock-tests	?
unit	76.8% <ø> (?)

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see 571 files with indirect coverage changes

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[Inphi]

I ran into the same issue and I was about to work on a fix. Thanks for doing this

[pauldowman]

kona e2e tests are failing with "Test killed with quit: ran too long (44m0s)"