Add ability to select header row from S3 ingest

Use case: I have an external application that I want to integrate with Gainsight. It produces a flat file that I want to import into Gainsight MDA. It's produced in a standard format, but contains some summary data in the first few rows (eg, report name, date, etc.) that I cannot remove. The actual data begins on row X, and is properly structured with uniform headers. If this were a 1 off upload I could easily remove the few extra rows. However, to set up a proper integration, I need to specify the row that contains column headers so that the data can be read on an ongoing basis. Currently this is possible in either the managed S3 bucket or the S3 Bionic Rule import feature.

At a very minimum, I'd recommend upgrading the error alert that's thrown when headers are not recognized in the source file (from S3 Bionic Rule) as it is not human readable and requires a support touch to decipher.