fix(table): remove header table cell background states

- there's not really color changes specc'd out for the header table cell
background states, so they're now removed

Author: marissahuysentruyt

components/table/index.css

@@ -183,11 +183,9 @@
 		--highcontrast-table-row-text-color: var(--highcontrast-table-row-text-color-focus);
 		--highcontrast-table-icon-color: var(--highcontrast-table-row-text-color-focus);
 		--spectrum-table-row-text-color: var(--spectrum-table-row-text-color-key-focus);
-		--spectrum-table-header-background-color: var(--spectrum-table-cell-background-color);
 
 		&:hover {
 			--spectrum-table-row-text-color: var(--spectrum-table-row-text-color-key-focus);
-			--spectrum-table-header-background-color: var(--spectrum-table-cell-background-color);
 		}
 	}
 
@@ -196,15 +194,13 @@
 		--highcontrast-table-icon-color: var(--highcontrast-table-row-text-color-hover);
 		--spectrum-table-cell-background-color: var(--highcontrast-table-row-background-color-hover, var(--mod-table-row-background-color-hover, var(--spectrum-table-row-background-color-hover)));
 		--spectrum-table-row-text-color: var(--highcontrast-table-row-text-color-hover, var(--mod-table-row-text-color-hover, var(--spectrum-table-row-text-color-hover)));
-		--spectrum-table-header-background-color: var(--spectrum-table-cell-background-color);
 	}
 
 	&:active {
 		--highcontrast-table-row-text-color: var(--highcontrast-table-row-text-color-hover);
 		--highcontrast-table-icon-color: var(--highcontrast-table-row-text-color-hover);
 		--spectrum-table-cell-background-color: var(--highcontrast-table-row-background-color-hover, var(--mod-table-row-background-color-active-color, var(--spectrum-table-row-background-color-active)));
 		--spectrum-table-row-text-color: var(--highcontrast-table-row-text-color-hover, var(--mod-table-row-text-color-active, var(--spectrum-table-row-text-color-active)));
-		--spectrum-table-header-background-color: var(--spectrum-table-cell-background-color);
 	}
 
 	&.is-selected {