Fix API variables formatting for meeting endTime and duration.

bbb-common-web/src/test/resources/get-meeting-info.ftlx

bbb-common-web/src/test/resources/get-meetings.ftlx

.../src/main/webapp/WEB-INF/freemarker/get-meeting-info.ftlx

...-web/src/main/webapp/WEB-INF/freemarker/get-meetings.ftlx