Remove prop heading-variant from kol-heading

[sdvg]

Refs: #7735

The A11y and PO reviews will only take place after all other DoD steps have been completed by the Developer:

• Meaningful pull request title for the release notes
• Pull request is linked to an issue and all changes relate to the issue
• Tests to protect this code implemented (if applicable)
• Manual test performed successfully (if applicable)
• Documentation or migration has been updated (if applicable)

[github-actions]

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[github-actions]

Hydration Benchmark Report (vs Baseline)

📊 Flop 5 Regressions

Component	Current	Baseline	Δ%	Result
kol-accordion	67ms	61ms	+9.8%	🔻
kol-table-stateful	72ms	68ms	+5.9%	🔻
kol-heading	23ms	22ms	+4.5%	➖
kol-split-button	51ms	49ms	+4.1%	➖
kol-input-password	30ms	29ms	+3.4%	➖

📋 Show all results

Component	Current	Baseline	Δ%	Result
kol-abbr	6ms	7ms	-14.3%	✅
kol-alert	21ms	22ms	-4.5%	➖
kol-avatar	9ms	9ms	0.0%	➖
kol-badge	28ms	29ms	-3.4%	➖
kol-breadcrumb	16ms	16ms	0.0%	➖
kol-button	49ms	49ms	0.0%	➖
kol-button-link	50ms	49ms	+2.0%	➖
kol-card	24ms	24ms	0.0%	➖
kol-details	54ms	56ms	-3.6%	➖
kol-drawer	9ms	9ms	0.0%	➖
kol-form	9ms	9ms	0.0%	➖
kol-icon	9ms	9ms	0.0%	➖
kol-image	5ms	6ms	-16.7%	✅
kol-input-checkbox	32ms	31ms	+3.2%	➖
kol-input-color	31ms	30ms	+3.3%	➖
kol-input-date	32ms	32ms	0.0%	➖
kol-input-email	33ms	33ms	0.0%	➖
kol-input-file	58ms	59ms	-1.7%	➖
kol-input-number	29ms	29ms	0.0%	➖
kol-input-radio	25ms	26ms	-3.8%	➖
kol-input-text	32ms	34ms	-5.9%	✅
kol-link	44ms	45ms	-2.2%	➖
kol-link-button	44ms	46ms	-4.3%	➖
kol-modal	7ms	7ms	0.0%	➖
kol-nav	10ms	10ms	0.0%	➖
kol-pagination	69ms	68ms	+1.5%	➖
kol-popover-button	49ms	50ms	-2.0%	➖
kol-progress	6ms	6ms	0.0%	➖
kol-quote	6ms	6ms	0.0%	➖
kol-select	28ms	28ms	0.0%	➖
kol-skip-nav	7ms	7ms	0.0%	➖
kol-spin	6ms	6ms	0.0%	➖
kol-table-stateless	70ms	69ms	+1.4%	➖
kol-tabs	10ms	10ms	0.0%	➖
kol-textarea	28ms	29ms	-3.4%	➖
kol-toolbar	6ms	6ms	0.0%	➖
kol-tree	9ms	9ms	0.0%	➖
kol-tree-item	51ms	50ms	+2.0%	➖
kol-version	40ms	40ms	0.0%	➖