chore(ci): Upgrade performance test apps to React Native 0.85.1 (#6088)

* chore(ci): Upgrade performance test apps to React Native 0.85.1

Closes https://github.com/getsentry/sentry-react-native/issues/4426

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* fix(ci): Set REACT_NATIVE_NODE_MODULES_DIR for perf test iOS builds

The podspec's node resolution finds packages/core/node_modules/react-native
(0.80.1) instead of the perf test app's (0.85.1) due to yarn workspace
symlink resolution. This causes NEW_HERMES_RUNTIME to not be defined,
and the old Hermes static profiling API (removed in RN 0.85) to be compiled.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* chore(ios): Bump iOS binary size limit from 1470 to 1550 KiB

The RN 0.80 to 0.85 upgrade increased the Sentry-vs-plain iOS binary
size diff from ~1.44 MiB to ~1.51 MiB.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* chore(ios): Relax iOS startup time diffMin from -20 to -3000

On RN 0.85.1, the iOS startup time test consistently shows the plain
app ~2.6s slower than the Sentry app. This is a measurement artifact
of using Appium's activateApp() duration rather than actual UI render
time — the command returns at different times based on binary
characteristics unrelated to SDK overhead.

Relaxing diffMin to -3000 for iOS only. Android keeps -20 as it
doesn't exhibit this behavior. The diffMax (150ms) still catches real
SDK overhead regressions.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

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Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>