feat: add Firefox and Webkit to karma

[weboko]

Problem

RIght now unit tests are run only in Chrome env.

Solution

We need to run them in other envs too.
In this PR FirefoxHeadless and WebkitHeadless are added.

Notes

• Dependant on feat: add playwright CI testing #1542
• Related to Cover Several Environments As Part of Testing #52

[github-actions]

size-limit report 📦

Path	Size	Loading time (3g)	Running time (snapdragon)	Total time
Waku core	27.69 KB (0%)	554 ms (0%)	1.9 s (+34.55% 🔺)	2.5 s
Waku Simple Light Node	262.6 KB (0%)	5.3 s (0%)	6.5 s (+70.44% 🔺)	11.8 s
ECIES encryption	28.7 KB (0%)	574 ms (0%)	2.3 s (+38.6% 🔺)	2.8 s
Symmetric encryption	28.7 KB (0%)	575 ms (0%)	1.7 s (-8.26% 🔽)	2.3 s
DNS discovery	110.62 KB (0%)	2.3 s (0%)	3.9 s (+31.97% 🔺)	6.1 s
Privacy preserving protocols	117.38 KB (0%)	2.4 s (0%)	3.6 s (+27.51% 🔺)	5.9 s
Light protocols	25.83 KB (0%)	517 ms (0%)	1.7 s (-2.41% 🔽)	2.2 s
History retrieval protocols	24.9 KB (0%)	499 ms (0%)	1.6 s (-12.17% 🔽)	2.1 s
Deterministic Message Hashing	5.65 KB (0%)	113 ms (0%)	406 ms (-7.38% 🔽)	519 ms

[fryorcraken]

Just some comment in terms of avoiding dupe code

[danisharora099]

similar comments as discussed above with:

• moving karma.config.js to root
• moving dependencies shared with packages to root

should be good to merge then!

[danisharora099]

similar comments as discussed above with:

• moving karma.config.js to root
• moving dependencies shared with packages to root

should be good to merge then!

@weboko looks like these were not addressed -- are we tracking them somewhere?