Fix grid rearrange bugs

[gbalint]

Problem:
This PR fixes 2 issues:

1. it is possible to drag a multicell child further to top/left and then it collapses
2. dragging a multicell child to top/left corner collapses it to the single top/left cell
3. width and height mismatch caused weird resize in multicell elements without explicit row or column setting.

Fix:

1. Restrict the target row/column to >0 numbers
2. Make sure multicell children are not reordered, but rearranged, because reorder deletes all explicit column/row properties
3. fix the crazy mistype in the code

and add tests!

Manual Tests:
I hereby swear that:

• I opened a hydrogen project and it loaded
• I could navigate to various routes in Play mode

[github-actions]

Try me

[relativeci]

#14683 Bundle Size — 57.93MiB (~+0.01%).

f766940(current) vs 916e8b9 master#14679(baseline)

Warning

Bundle contains 70 duplicate packages – View duplicate packages

Bundle metrics   2 changes 1 regression

	Current #14683	Baseline #14679
Initial JS	40.93MiB(~+0.01%)	40.93MiB
Initial CSS	0B	0B
Cache Invalidation	17.93%	0%
Chunks	21	21
Assets	23	23
Modules	4142	4142
Duplicate Modules	213	213
Duplicate Code	27.32%	27.32%
Packages	477	477
Duplicate Packages	70	70

Bundle size by type   2 changes 1 regression 1 improvement

	Current #14683	Baseline #14679
JS	57.92MiB (~+0.01%)	57.92MiB
HTML	7.37KiB (-0.25%)	7.39KiB

Bundle analysis report Branch fix/grid-rearrange Project dashboard

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