FIX Add one to current colspan in fixColumns instead of resetting to 2

[Kevinn1109]

Description

In the old situation, the final column in each row would be hardcoded to colspan="2" if the function 'fixColumns' was called. This is required because this function adds an additional column to the table that needs to be filled in. This change removes the hardcoded number and instead adds one to the current colspan of the last cell. This fixes the bug that the 'No items found' row would be capped at two columns even if the table has more.

Manual testing steps

1. Manually create a GridField for an has_many relation that contains no records, this should fullfill the check in needsColumnFix by default. The relation class should have at least 3 summary fields.
2. Without this change, the 'No items found' row gets a colspan of 2. With this change, it should be 4.

Issues

• Empty GridField without actions creates a 'No items found' row hardcoded to span only two columns #1859

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[GuySartorelli]

Thanks! Couple of small changes

[GuySartorelli]

#1869 (comment) hasn't been responded to. We're assuming if the colspan wasn't defined, it is already 1 and should become 2. Does that always hold true? Can we do something like count the number of columns in the table or something?

[Kevinn1109]

#1869 (comment) hasn't been responded to. We're assuming if the colspan wasn't defined, it is already 1 and should become 2. Does that always hold true? Can we do something like count the number of columns in the table or something?

The calling function adds one column to the table, so a correctly set up table will always have rows with the number of columns minus that new column. My change changes a hardcoded 2 that disregards the existing colspan to something that takes it into account. Counting the number of columns isn't needed, the entire purpose of this function is to add one column. If this leads to a wrong number of columns, there's a near certainty that said table already has a wrong number of columns in the current release. As far as I can tell, the only native integration that's affected by this is the 'No items found' row.

In my eyes this is legacy code that should be removed altogether, but I'm not entirely sure if that comes with complications or not.

[GuySartorelli]

Looks good, thanks! Just letting CI run and I'll merge if it's green.