Graph: Fixed tooltip highlight on white theme (#16429)

Fixes #16359

packages/grafana-ui/src/themes/light.ts

@@ -65,7 +65,7 @@ const lightTheme: GrafanaTheme = {
     text: basicColors.gray1,
     textStrong: basicColors.dark2,
     textWeak: basicColors.gray2,
-    textEmphasis: basicColors.gray5,
+    textEmphasis: basicColors.dark5,
     textFaint: basicColors.dark4,
     link: basicColors.gray1,
     linkDisabled: new tinycolor(basicColors.gray1).lighten(30).toString(),

public/sass/_variables.light.generated.scss

@@ -76,7 +76,7 @@ $text-color: #52545c;
 $text-color-strong: #41444b;
 $text-color-weak: #767980;
 $text-color-faint: #35373f;
-$text-color-emphasis: #dde4ed;
+$text-color-emphasis: #41444b;
 
 $text-shadow-faint: none;