Fix duplicating br tags in html

Author: dk981234

src/flat_layout/flat_html.ts

@@ -24,7 +24,7 @@ export class FlatHTML extends FlatQuestion {
     }
 
     private static correctHtmlRules: [{ searchRegExp: RegExp, replaceString: string }] = [
-        { searchRegExp: /(<\/?br\s*?\/?\s*?>\s*){2,}/, replaceString: '<br>' }
+        { searchRegExp: /(<\/?br\s*?\/?\s*?>\s*){2,}/g, replaceString: '<br>' }
     ]
     protected correctHtml(html: string): string {
         FlatHTML.correctHtmlRules.forEach((rule) => {

tests/flat_html.test.ts

@@ -86,6 +86,8 @@ test('Check correctHtml method with multiple br tags', async () => {
     const htmlFlat = new FlatHTML(survey, new QuestionHtmlModel('q1'), controller);
     expect(htmlFlat['correctHtml']('<span>Test</span><br>')).toEqual('<span>Test</span><br>');
     expect(htmlFlat['correctHtml']('<span>Test</span><br><br>')).toEqual('<span>Test</span><br>');
+    expect(htmlFlat['correctHtml']('<br><br><span>Test</span><br><br>')).toEqual('<br><span>Test</span><br>');
+    expect(htmlFlat['correctHtml']('<br><br><span>Test</span><br><br><br><span>Test</span><br><br>')).toEqual('<br><span>Test</span><br><span>Test</span><br>');
     expect(htmlFlat['correctHtml']('<span>Test</span><br>  <br>')).toEqual('<span>Test</span><br>');
     expect(htmlFlat['correctHtml']('<br><span>Test</span><br>')).toEqual('<br><span>Test</span><br>');
     expect(htmlFlat['correctHtml']('<br><br/>')).toEqual('<br>');