Make tab components use `text-dark` color (#28056)

frontend/src/metabase/core/components/Tab/Tab.styled.tsx

@@ -14,7 +14,7 @@ export const TabRoot = styled.button<TabProps>`
   flex: 1;
   text-align: left;
 
-  color: ${props => (props.isSelected ? color("brand") : color("text-light"))};
+  color: ${props => (props.isSelected ? color("brand") : color("text-dark"))};
   background-color: ${props =>
     props.isSelected ? alpha("brand", 0.1) : "transparent"};
   cursor: pointer;

frontend/src/metabase/core/components/TabLink/TabLink.styled.tsx

@@ -16,7 +16,7 @@ export const TabLabel = styled.div`
 export const TabLinkRoot = styled(Link)<TabLinkProps>`
   padding: 1rem 0;
 
-  color: ${props => (props.isSelected ? color("brand") : color("text-medium"))};
+  color: ${props => (props.isSelected ? color("brand") : color("text-dark"))};
   font-size: 0.875rem;
   font-weight: 700;