Output actual MySQL warning messages when inserting occurrence data in SpecUploadBase

[esamelson]

We had an issue recently where a duplicated occurrenceID value was presenting a large dataset from being uploaded and inserted using the specupload tools. Because the actual MySQL warning message was suppressed and replaced with a more generic message, it was difficult to track down the actual issue (and offending data).

This change replaces the generic message from Symbiota with the actual MySQL warning message. (It also removes the check for the now-outdated name of the index.) Our database manager found this change very helpful for troubleshooting, so just wanted to submit it as an option in case you'd like to adopt.

Pull Request Checklist:

Pre-Approval

• There is a description section in the pull request that details what the proposed changes do. It can be very brief if need be, but it ought to exist.
• Hotfixes should be branched off of the master branch and PR'd using the merge option (not squashed) into the hotfix branch.
• Features and backlog bugs should be merged into the Development branch, NOT master
• All new text is preferably internationalized (i.e., no end-user-visible text is hard-coded on the PHP pages), and the spreadsheet tracking internationalizations has been updated either with a new row or with checkmarks to existing rows.
• There are no linter errors
• New features have responsive design (i.e., look aesthetically pleasing both full screen and with small or mobile screens)
• Symbiota coding standards have been followed
• If any files have been reformatted (e.g., by an autoformatter), the reformat is its own, separate commit in the PR
• Comment which GitHub issue(s), if any does this PR address
• If this PR makes any changes that would require additional configuration of any Symbiota portals outside of the files tracked in this repository, make sure that those changes are detailed in this document.

Post-Approval

• It is the code author's responsibility to merge their own pull request after it has been approved
• If this PR represents a merge into the Development branch, remember to use the squash & merge option
• If this PR represents a merge into the hotfix branch, remember to use the merge option (i.e., no squash).
• If this PR represents a merge from the Development branch into the master branch, remember to use the merge option
• If this PR represents a merge from the hotfix branch into the master branch use the squash & merge option
  • a subsequent PR from master into Development should be made with the merge option (i.e., no squash).
  • Immediately delete the hotfix branch and create a new hotfix branch
  • increment the Symbiota version number in the symbase.php file and commit to the hotfix branch.
• If the dev team has agreed that this PR represents the last PR going into the Development branch before a tagged release (i.e., before an imminent merge into the master branch), make sure to notify the team and lock the Development branch to prevent accidental merges while QA takes place. Follow the release protocol here.
• Don't forget to delete your feature branch upon merge. Ignore this step as required.

Thanks for contributing and keeping it clean!