[pickers] Update date calendar styling

[LukasTy]

Fixes #9276

After many experiments, I've gone with fixed width container for this version, just because we have so many possible props that can impact the layout and make it very hard to handle responsive container width.
We also preferably do not want to increase the container width past 320px, at least for now.

• Revert change made in [pickers] Inherit previous and next icons size from their parent button #8218 based on [pickers] Can't change the size of the previous / next icons #8206 (comment)

[mui-bot]

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Updated pages

No updates.

These are the results for the performance tests:

Test case	Unit	Min	Max	Median	Mean	σ
Filter 100k rows	ms	515.5	978.5	844.1	750.38	191.682
Sort 100k rows	ms	610.3	1,131.4	787.7	844.8	171.663
Select 100k rows	ms	215.9	392.7	294.8	300.64	56.334
Deselect 100k rows	ms	142.3	285.3	221.6	219.36	45.603

Generated by 🚫 dangerJS against e0af0d7

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