tests: fix flaky e2e multisig tests

[cce]

Summary

In the multisig e2e tests, msgpacktool -d | grep -q runs under set -o pipefail, so when grep -q exits right after matching "lmsig"/"msig", msgpacktool might still be writing and encounter EPIPE, leading to a non-zero status reported and a failed test.

Test Plan

Tests should be hopefully less flaky.

[Copilot]

Pull Request Overview

This PR fixes flaky e2e multisig tests caused by race conditions when piping msgpacktool -d output to grep -q. The issue occurs because grep -q exits immediately after finding a match, which can cause msgpacktool to receive EPIPE while still writing, resulting in non-zero exit status under set -o pipefail.

Key Changes:

• Split the pipeline operation into two separate steps: decode to file, then grep the file
• Eliminates the race condition by ensuring msgpacktool completes before grep runs

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
test/scripts/e2e_subs/v32/e2e-teal-multisig.sh	Breaks pipeline into separate decode and grep steps for v32 legacy mode test
test/scripts/e2e_subs/e2e-teal-multisig.sh	Breaks pipeline into separate decode and grep steps for future consensus mode test

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[jannotti]

We should probably comment on this, so that someone doesn't tidy it up some day to avoid the temp file.