ui tests: support a regular expression for popup text

The popup text may contain placeholder, like the name of the
participant. It should be possible to specify a regular expression for
the `popupText` of the `inputPopupButtonTest`.

Example usage: if a popup has a text with `Hello {{nickname}}`, we can
send `/Hello .*/` for the popupText value instead of a string `"Hello I
don't know what to put here"`.

Author: tahini

packages/evolution-frontend/tests/ui-testing/testHelpers.ts

@@ -76,7 +76,7 @@ type InputCheckboxTest = (params: { path: Path; values: Value[] } & CommonTestPa
 type InputMapFindPlaceTest = (params: { path: Path } & CommonTestParameters) => void;
 type WaitForMapLoadedTest = (params: CommonTestParameters) => void;
 type InputNextButtonTest = (params: { text: Text; nextPageUrl: Url } & CommonTestParameters) => void;
-type InputPopupButtonTest = (params: { text: Text; popupText: Text } & CommonTestParameters) => void;
+type InputPopupButtonTest = (params: { text: Text; popupText: Text | RegExp } & CommonTestParameters) => void;
 type RedirectionTest = (
     params: { buttonText: Text; expectedRedirectionUrl: Url; nextPageUrl: Url } & CommonTestParameters
 ) => void;