[Scripts]: Remove --with-deps from tests' postinstall

[mfaarni]

DS-681

The postinstall script for tests folder included --with-deps, which is used to install Playwright's browser libraries. This is a Linux specific command, as MacOS handles the dependencies differently. When running Linux, this caused the npm install command to prompt the user for their password for sudo, but the npm loading spinner obstructed the input field which made the install get stuck.

To my knowledge, the required dependencies are usually already installed. To be sure that even first timers have them, I included a command to install the deps manually in the Getting Started-section of the docs.

Developer's checklist

• I wrote necessary unit tests
• I updated Storybook stories and documentation to reflect the latest changes
• I included visual regression tests for new UI design
• I tested my implementation with different browsers
• I checked accessibility according to Web Content Accessibility Guidelines 2.1
• Together with the reviewer I can confirm that the implementation supports the following screenreader and browser combinations (NVDA + Firefox, VoiceOver + Chrome)

[github-actions]

Lines	Statements	Branches	Functions
	94.97% (14137/14885)	89.28% (1425/1596)	91.08% (531/583)

Coverage Report • (94%)

File	% Stmts	% Branch	% Funcs	% Lines	Uncovered Line #s
All files	94.97	89.28	91.08	94.97

report-only-changed-files is enabled. No files were changed in this commit :)

[emilyhernandez]

Seems to work well locally 👍