fluent-ui: Allow value of 0 in TextWidget (#2497)

* Update TextWidget.tsx

Fixes proper undefined/null check and not falsy check.  when value is 0 its changed to "" instead of "0"

* Update packages/fluent-ui/src/TextWidget/TextWidget.tsx

Co-authored-by: Ashwin Ramaswami <[email protected]>

Author: pksorensen

packages/fluent-ui/src/TextWidget/TextWidget.tsx

@@ -84,7 +84,7 @@ const TextWidget = ({
       // TODO: once fluent-ui supports the name prop, we can add it back in here.
       // name={name}
       type={inputType as string}
-      value={value ? value : ""}
+      value={value || value === 0 ? value : ""}
       onChange={_onChange as any}
       onBlur={_onBlur}
       onFocus={_onFocus}