Avoid assigning to readonly style

[JoviDeCroock]

Fixes: #2722

@charlier if you get the chance you can use our pika-distribution (one of the PR-checks) to see if it works locally for you.

[github-actions]

Coverage decreased (-0.8%) to 99.022% when pulling 9899efa on avoid-assigning-to-readonly-style into a574a9e on master.

[marvinhagemeister]

Good catch! I recall us having assigned to cssText earlier in our code base 👍

[github-actions]

Size Change: +22 B (0%)

Total Size: 40.4 kB

Filename	Size	Change
dist/preact.js	3.91 kB	+6 B (0%)
dist/preact.min.js	3.93 kB	+5 B (0%)
dist/preact.module.js	3.93 kB	+6 B (0%)
dist/preact.umd.js	3.97 kB	+5 B (0%)

ℹ️ View Unchanged

Filename	Size	Change
compat/dist/compat.js	3.26 kB	0 B
compat/dist/compat.module.js	3.29 kB	0 B
compat/dist/compat.umd.js	3.33 kB	0 B
debug/dist/debug.js	3.09 kB	0 B
debug/dist/debug.module.js	3.09 kB	0 B
debug/dist/debug.umd.js	3.18 kB	0 B
devtools/dist/devtools.js	185 B	0 B
devtools/dist/devtools.module.js	195 B	0 B
devtools/dist/devtools.umd.js	261 B	0 B
hooks/dist/hooks.js	1.09 kB	0 B
hooks/dist/hooks.module.js	1.11 kB	0 B
hooks/dist/hooks.umd.js	1.17 kB	0 B
test-utils/dist/testUtils.js	437 B	0 B
test-utils/dist/testUtils.module.js	439 B	0 B
test-utils/dist/testUtils.umd.js	515 B	0 B

_{compressed-size-action}

[klh]

this causes IE11 to fail making preact 10.4.7 and 10.4.8 incompatible with IE11.

[JoviDeCroock]

@klh no this fixes that, this PR is aimed at fixing the linked issue which is what you're describing. This is currently unpublished