Multiple test utils relays

[benalleng]

This adjusts the initialize ohttp_relay function within test utils to be able to spin up any number of relays. This came about following the addition of 36e1f6b in #1399 where every e2e test now produces a warning. In addition this PR can come in handy when we begin to flesh out the ASmap random selection to be able to better prove out its usefulness.

Written with the help of deepseek v4 flash

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[coveralls]

Coverage Report for CI Build 27160164202

Coverage increased (+0.006%) to 85.391%

Details

• Coverage increased (+0.006%) from the base build.
• Patch coverage: 3 uncovered changes across 1 file (28 of 31 lines covered, 90.32%).
• No coverage regressions found.

Uncovered Changes

File	Changed	Covered	%
payjoin-test-utils/src/v2.rs	31	28	90.32%

Coverage Regressions

No coverage regressions found.

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Coverage Stats

Relevant Lines:	14710
Covered Lines:	12561
Line Coverage:	85.39%
Coverage Strength:	372.15 hits per line

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💛 - Coveralls

[xstoicunicornx]

utACK b62a9f1

Updates are straightforward and sensible. As a reference implementation, payjoin-cli tests should reflect that having multiple relays available for usage is the expected behavior.