[atable] make modal placement dynamic

[Alchez]

Work towards a fix for https://github.com/agritheory/fab/pull/20.

[github-actions]

Coverage Report for ./atable

Status	Category	Percentage	Covered / Total
🔴	Lines	66.49% (🎯 70%)	129 / 194
🔴	Statements	67.15% (🎯 70%)	137 / 204
🟢	Functions	75% (🎯 70%)	30 / 40
🔴	Branches	44.93% (🎯 70%)	71 / 158

File Coverage

File	Stmts	% Branch	% Funcs	% Lines	Uncovered Lines
Changed Files
atable/src/components/ACell.vue	93.33%	56.09%	100%	93.33%	86, 106, 128-131, 174
atable/src/components/ATable.vue	51.92%	32.5%	88.88%	51.02%	107, 110-112, 111, 117, 120-128, 124-127, 126, 131-147, 132-133, 135-141, 136-140, 137-139, 143-146, 144-145, 203-205, 204, 204
Unchanged Files
atable/src/components/AExpansionRow.vue	0%	0%	0%	0%	33-34, 37-39, 38, 41-60, 42-48, 44-46, 50-52, 51, 54-59, 1, 3
atable/src/components/ARow.vue	66.66%	56%	71.42%	63.63%	56, 63, 67, 71, 73-78, 74-77, 80-85, 17
atable/src/components/ATableHeader.vue	100%	50%	100%	100%
atable/src/components/ATableModal.vue	50%	100%	0%	50%	29
atable/src/components/index.ts	65.9%	50%	66.66%	66.66%	47-49, 48, 61, 84-86, 85, 104-116, 105-113, 106-112, 108-111, 110, 114-116, 115

Generated in workflow #361 for commit 5b40d59 by the Vitest Coverage Report Action