Chore: Remove several instances of non-strict null usage (#20563)

packages/grafana-ui/src/components/Collapse/Collapse.tsx

@@ -83,7 +83,7 @@ const getStyles = stylesFactory((theme: GrafanaTheme) => ({
 }));
 
 interface Props {
-  isOpen: boolean;
+  isOpen?: boolean;
   label: string;
   loading?: boolean;
   collapsible?: boolean;

packages/grafana-ui/src/components/Graph/Graph.tsx

@@ -14,7 +14,7 @@ export interface GraphProps {
   children?: JSX.Element | JSX.Element[];
   series: GraphSeriesXY[];
   timeRange: TimeRange; // NOTE: we should aim to make `time` a property of the axis, not force it for all graphs
-  timeZone: TimeZone; // NOTE: we should aim to make `time` a property of the axis, not force it for all graphs
+  timeZone?: TimeZone; // NOTE: we should aim to make `time` a property of the axis, not force it for all graphs
   showLines?: boolean;
   showPoints?: boolean;
   showBars?: boolean;
@@ -246,7 +246,7 @@ export class Graph extends PureComponent<GraphProps, GraphState> {
         label: 'Datetime',
         ticks: ticks,
         timeformat: timeFormat(ticks, min, max),
-        timezone: timeZone ? timeZone : DefaultTimeZone,
+        timezone: timeZone ?? DefaultTimeZone,
       },
       yaxes,
       grid: {

packages/grafana-ui/src/components/Logs/LogRows.tsx

@@ -16,7 +16,7 @@ export interface Props extends Themeable {
   logRows?: LogRowModel[];
   deduplicatedRows?: LogRowModel[];
   dedupStrategy: LogsDedupStrategy;
-  highlighterExpressions: string[];
+  highlighterExpressions?: string[];
   showTime: boolean;
   timeZone: TimeZone;
   rowLimit?: number;

packages/grafana-ui/src/components/RefreshPicker/RefreshPicker.tsx

@@ -37,7 +37,7 @@ export interface Props {
 export class RefreshPickerBase extends PureComponent<Props> {
   static offOption = { label: 'Off', value: '' };
   static liveOption = { label: 'Live', value: 'LIVE' };
-  static isLive = (refreshInterval: string): boolean => refreshInterval === RefreshPicker.liveOption.value;
+  static isLive = (refreshInterval?: string): boolean => refreshInterval === RefreshPicker.liveOption.value;
 
   constructor(props: Props) {
     super(props);