test: disable parallel install of packages in e2e test

[vmasek]

This PR should fix the error present locally & in CI, that has been caused by parallel nxv-pkg-install rewriting the package.json when installing dependencies in the per e2e tmp folder.

The error was recognizable in the logs as:
Cannot find package '@code-pushup/plugin-****' imported from ... code-pushup.config.bundled_****
This was happening randomly, only if the "plugin" was not installed last as it did not rewrite any of the important deps (cli, core,...), but if if was installed sooner, the specific package (cli, core, ...) would emit package.json without the plugin or any other important dependency.

Detailed examples of failing PRs

Example from recent PR

Error [ERR_MODULE_NOT_FOUND]: Cannot find package '@code-pushup/js-packages-plugin' imported from /Users/runner/work/cli/cli/tmp/e2e/plugin-js-packages-e2e/__test__/npm-repo/code-pushup.config.bundled_rv4w9bp3q0b.mjs

Example from another PR

Error [ERR_MODULE_NOT_FOUND]: Cannot find package '@code-pushup/jsdocs-plugin' imported from /Users/runner/work/cli/cli/tmp/e2e/plugin-jsdocs-e2e/__test__/angular/code-pushup.config.bundled_6o2x8onjd6g.mjs

[github-actions]

Code PushUp

🤨 Code PushUp report has both improvements and regressions – compared current commit 0e3cb8d with previous commit 5f0a8c4.

🕵️ See full comparison in Code PushUp portal 🔍

🏷️ Categories

🏷️ Category	⭐ Previous score	⭐ Current score	🔄 Score change
Performance	🟡 50	🔴 49
Code coverage	🟢 90	🟢 90	–
Security	🟡 62	🟡 62	–
Updates	🟡 84	🟡 84	–
Accessibility	🟢 92	🟢 92	–
Best Practices	🟢 100	🟢 100	–
SEO	🟡 61	🟡 61	–
Type Safety	🟢 100	🟢 100	–
Bug prevention	🟢 100	🟢 100	–
Miscellaneous	🟢 100	🟢 100	–
Code style	🟢 100	🟢 100	–
Documentation	🔴 23	🔴 23	–

👎 1 group regressed, 👍 2 audits improved, 👎 4 audits regressed, 11 audits changed without impacting score

🗃️ Groups

🔌 Plugin	🗃️ Group	⭐ Previous score	⭐ Current score	🔄 Score change
Lighthouse	Performance	🟡 50	🔴 49

20 other groups are unchanged.

🛡️ Audits

🔌 Plugin	🛡️ Audit	📏 Previous value	📏 Current value	🔄 Value change
Lighthouse	Initial server response time was short	🟥 Root document took 810 ms	🟩 Root document took 570 ms
Lighthouse	Speed Index	🟥 6.4 s	🟨 5.7 s
Lighthouse	First Contentful Paint	🟨 3.0 s	🟥 3.1 s
Lighthouse	Largest Contentful Paint	🟨 3.6 s	🟨 3.8 s
Lighthouse	Time to Interactive	🟥 13.1 s	🟥 14.1 s
Lighthouse	Total Blocking Time	🟥 2,750 ms	🟥 3,580 ms
Lighthouse	Minimizes main-thread work	🟥 13.0 s	🟥 15.2 s
Lighthouse	Metrics	🟩 100%	🟩 100%
Lighthouse	Max Potential First Input Delay	🟥 1,670 ms	🟥 2,560 ms
Lighthouse	Uses efficient cache policy on static assets	🟨 27 resources found	🟨 27 resources found
Lighthouse	Server Backend Latencies	🟩 260 ms	🟩 190 ms
Lighthouse	Avoids enormous network payloads	🟩 Total size was 1,839 KiB	🟩 Total size was 1,839 KiB
Lighthouse	JavaScript execution time	🟥 6.3 s	🟥 6.3 s
Lighthouse	Eliminate render-blocking resources	🟥 Potential savings of 1,020 ms	🟥 Potential savings of 1,000 ms
Lighthouse	Network Round Trip Times	🟩 70 ms	🟩 70 ms
Lighthouse	Avoid large layout shifts	🟩 0	🟩 1 layout shift found
Lighthouse	Cumulative Layout Shift	🟩 0	🟩 0.001

586 other audits are unchanged.