Chore: strictNullChecks, ColoringEditor and time_region_manager (#18442)

* Make swicth booleans non-optional

public/app/plugins/panel/graph/time_region_manager.ts

@@ -4,8 +4,8 @@ import { GrafanaThemeType, getColorFromHexRgbOrName } from '@grafana/ui';
 import { dateTime, DateTime, AbsoluteTimeRange } from '@grafana/data';
 
 type TimeRegionColorDefinition = {
-  fill: string;
-  line: string;
+  fill: string | null;
+  line: string | null;
 };
 
 export const colorModes: any = {

public/app/plugins/panel/singlestat2/types.ts

@@ -13,10 +13,10 @@ export interface SingleStatOptions extends SingleStatBaseOptions {
   prefixFontSize?: string;
   valueFontSize?: string;
   postfixFontSize?: string;
-  colorBackground?: boolean;
-  colorValue?: boolean;
-  colorPrefix?: boolean;
-  colorPostfix?: boolean;
+  colorBackground: boolean;
+  colorValue: boolean;
+  colorPrefix: boolean;
+  colorPostfix: boolean;
   sparkline: SparklineOptions;
 }
 
@@ -44,4 +44,8 @@ export const defaults: SingleStatOptions = {
   },
   fieldOptions: standardFieldDisplayOptions,
   orientation: VizOrientation.Auto,
+  colorBackground: false,
+  colorValue: false,
+  colorPrefix: false,
+  colorPostfix: false,
 };