Fix typo in regex_edit_dialog_container.ts. (tensorflow#6769)

## Motivation for features / changes
Fix a typo `darkModeEanbled` -> `darkModeEnabled `
## Technical description of changes
Fixing a typo made in code. Although it doesn't change functionality, it
keeps the code health.
## Screenshots of UI changes (or N/A)
N/A
## Detailed steps to verify changes work correctly (as executed by you)
N/A
## Alternate designs / implementations considered (or N/A)
N/A

Author: Anuar Talipov

tensorboard/webapp/runs/views/runs_table/regex_edit_dialog_container.ts

@@ -141,7 +141,7 @@ export class RegexEditDialogContainer {
                 colorPalette.colors[
                   groupKeyToColorString.size % colorPalette.colors.length
                 ];
-              colorHex = darkModeEanbled ? color.darkHex : color.lightHex;
+              colorHex = darkModeEnabled ? color.darkHex : color.lightHex;
               groupKeyToColorString.set(groupId, colorHex);
             }
             colorRunPairList.push({groupId, color: colorHex, runs});