WCAG AA fix for darkmode grayToWhite

Author: ascholerChemeketa

bases/rsptx/interactives/ptxrs-bootstrap.less

@@ -46,7 +46,7 @@
     --links: #7289da;
     --bodyFont: var(--body-text-color, #99aab5);
     --tooltip: #000000;
-    --grayToWhite: #aaa;
+    --grayToWhite: #e1e1e1;  /* AA compliant against known backgrounds */
     --navbar: #3d3d3d;
     --navbarFont: #ffffff;
     --navbarFontHover: #d6d6d6;