Make FieldKey.fromFieldKey return null for invalid input

[labkey-tchad]

Rationale

I removed this try/catch, hoping this could be a bit more strict but it's causing errors.

java.lang.IllegalArgumentException: FieldKey can't have blank part(s):
        at org.labkey.test.params.FieldKey.child(FieldKey.java:111)
        at org.labkey.test.params.FieldKey.fromParts(FieldKey.java:52)
        at org.labkey.test.params.FieldKey.fromFieldKey(FieldKey.java:76)
        at org.labkey.test.components.ui.grids.FieldReferenceManager.lambda$2(FieldReferenceManager.java:63)
        [...]
        at org.labkey.test.components.ui.grids.FieldReferenceManager.findFieldReference(FieldReferenceManager.java:72)
        at org.labkey.test.components.ui.grids.FieldReferenceManager.findFieldReferenceOrNull(FieldReferenceManager.java:80)
        at org.labkey.test.util.DataRegionTable$Elements.getColumnIndex(DataRegionTable.java:1532)
        at org.labkey.test.util.DataRegionTable.getColumnIndexStrict(DataRegionTable.java:421)
        at org.labkey.test.util.DataRegionTable.getDataAsText(DataRegionTable.java:675)

Related Pull Requests

• Refactor DataRegionTable to handle tricky characters better #2513

Changes

• Make FieldKey.fromFieldKey return null for invalid input

[labkey-jeckels]

Looks like a straightforward revert of a recent change. Maybe worth a comment as to why it's importing to return null to prevent future similar attempts?