add playwright testing for pixel checking

[Madoshakalaka]

Description

This PR adds playwright to our workflows to enable us to take screenshot and assert pixel colors.

It will help test #3892 and #3875

A test is added for #3875 as a starter.

Fixes #0000

Checklist

• I have reviewed my own code
• I have added tests

[github-actions]

Size Comparison

Details

examples	master (KB)	pull request (KB)	diff (KB)	diff (%)
async_clock	99.421	99.421	0	0.000%
boids	168.201	168.201	0	0.000%
communication_child_to_parent	91.780	91.780	0	0.000%
communication_grandchild_with_grandparent	102.800	102.800	0	0.000%
communication_grandparent_to_grandchild	97.798	97.798	0	0.000%
communication_parent_to_child	87.694	87.694	0	0.000%
contexts	103.902	103.902	0	0.000%
counter	84.495	84.495	0	0.000%
counter_functional	84.851	84.851	0	0.000%
dyn_create_destroy_apps	87.430	87.430	0	0.000%
file_upload	98.548	98.548	0	0.000%
function_memory_game	169.780	169.780	0	0.000%
function_router	336.910	336.910	0	0.000%
function_todomvc	162.883	162.883	0	0.000%
futures	235.953	235.953	0	0.000%
game_of_life	104.456	104.456	0	0.000%
immutable	194.165	194.165	0	0.000%
inner_html	80.152	80.152	0	0.000%
js_callback	107.565	107.565	0	0.000%
keyed_list	195.413	195.413	0	0.000%
mount_point	83.513	83.513	0	0.000%
nested_list	112.625	112.625	0	0.000%
node_refs	90.870	90.870	0	0.000%
password_strength	1782.886	1782.886	0	0.000%
portals	92.658	92.658	0	0.000%
router	306.364	306.364	0	0.000%
suspense	111.577	111.577	0	0.000%
timer	88.664	88.664	0	0.000%
timer_functional	94.691	94.691	0	0.000%
todomvc	143.130	143.130	0	0.000%
two_apps	85.872	85.872	0	0.000%
web_worker_fib	134.949	134.949	0	0.000%
web_worker_prime	185.107	185.107	0	0.000%
webgl	83.009	83.009	0	0.000%

✅ None of the examples has changed their size significantly.