SnpEff: distinguish between tool version and internal snpeff version …

[wm75]

…string

FOR CONTRIBUTOR:

• I have read the CONTRIBUTING.md document and this tool is appropriate for the tools-iuc repo.
• License permits unrestricted use (educational + commercial)
• This PR adds a new tool or tool collection
• This PR updates an existing tool or tool collection
• This PR does something else (explain below)

[wm75]

should fix #6571

No version bump because it seems reasonable to mask the broken version.

@bgruening @nsoranzo review welcome :-)

[wm75]

The issue is that SnpEff databases state their version in the metadata like this:

so validating against the tool version makes no sense.

[nsoranzo]

Also addresses https://github.com/galaxyproject/tools-iuc/pull/6387/files#r1807091037 .