Use template strings for string concatenation in JS code in dags.html (#13957)
Use template strings for string concatenation in JS code in dags.html (#13957)

- use template strings over '+'
- fix bugs caused by '+' concatenation
sekikn/incubator-airflow,Acehaidrey/incubator-airflow,danielvdende/incubator-airflow,dhuang/incubator-airflow,apache/airflow,nathanielvarona/airflow,cfei18/incubator-airflow,danielvdende/incubator-airflow,apache/airflow,mistercrunch/airflow,Acehaidrey/incubator-airflow,Acehaidrey/incubator-airflow,cfei18/incubator-airflow,Acehaidrey/incubator-airflow,lyft/incubator-airflow,cfei18/incubator-airflow,danielvdende/incubator-airflow,bolkedebruin/airflow,dhuang/incubator-airflow,apache/airflow,nathanielvarona/airflow,dhuang/incubator-airflow,cfei18/incubator-airflow,lyft/incubator-airflow,bolkedebruin/airflow,bolkedebruin/airflow,nathanielvarona/airflow,lyft/incubator-airflow,mistercrunch/airflow,apache/incubator-airflow,nathanielvarona/airflow,lyft/incubator-airflow,danielvdende/incubator-airflow,Acehaidrey/incubator-airflow,bolkedebruin/airflow,nathanielvarona/airflow,sekikn/incubator-airflow,Acehaidrey/incubator-airflow,mistercrunch/airflow,mistercrunch/airflow,apache/airflow,sekikn/incubator-airflow,apache/incubator-airflow,cfei18/incubator-airflow,sekikn/incubator-airflow,nathanielvarona/airflow,apache/airflow,danielvdende/incubator-airflow,apache/incubator-airflow,bolkedebruin/airflow,cfei18/incubator-airflow,apache/incubator-airflow,dhuang/incubator-airflow,apache/airflow,danielvdende/incubator-airflow