Warn about index.mapper.dynamic usage instead of erroring
#4016
| Job | Run time |
|---|---|
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| 13m 54s | |
| 37m 6s | |
| 10m 9s | |
| 11m 17s | |
| 31m 17s | |
| 9m 54s | |
| 12m 24s | |
| 29m 29s | |
| 2h 46m 19s |