build: Fix e2e tests for builds on v0.85

[mofojed]

• The edge version of deephaven-core installs the latest version of deephaven.ui, which is not compatible with this old version of the UI
• Just pin the e2e tests to an older build of core

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 46.65%. Comparing base (552f4d7) to head (a57bcd2).

Additional details and impacted files

@@              Coverage Diff               @@
##           release/v0.85    #2316   +/-   ##
==============================================
  Coverage          46.65%   46.65%           
==============================================
  Files                685      685           
  Lines              38495    38495           
  Branches            9590     9590           
==============================================
  Hits               17961    17961           
  Misses             20524    20524           
  Partials              10       10           

Flag	Coverage Δ
unit	46.65% <ø> (ø)

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