chore: use e2e updater url for e2e builds

[piotr-iohk]

This PR points E2E builds to a separate updater release.json hosted in bitkit-e2e-tests, so production critical updates don't block E2E test runs.

Description

The production updater currently has critical: true for both platforms. E2E builds from master with lower build numbers hit the blocking update screen immediately, making all tests fail.

When isE2E is true, updaterUrl now resolves to:
https://github.com/synonymdev/bitkit-e2e-tests/releases/download/updater/release.json

That file has buildNumber: 0, critical: false by default, so E2E builds are never blocked. When update flow testing is needed, the E2E release.json can be updated independently.

Linked Issues/Tasks

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Screenshot / Video

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Made with Cursor

[claude]

Code review

No issues found. Checked for bugs and CLAUDE.md compliance.

[ovitrif]

lgtm

[pwltr]

Maybe better to get into the habit of making sure build number updates make it to master before release (and consequent updating of release.json). This is an annoyance in development as well.

[piotr-iohk]

Maybe better to get into the habit of making sure build number updates make it to master before release (and consequent updating of release.json). This is an annoyance in development as well.

I believe they do make it to master before release.json update. But if particular branch is not updated then there is an issue.
(Also if you want to build some older versions to e.g. test migration)