Fixes
https://twenty-v7.sentry.io/issues/7398810663/?project=4507072563183616
## Bug description
The mergeMultipleRecords command's conditionalAvailabilityExpression
used numberOfSelectedRecords >= 2, which evaluates correctly in both
selection and exclusion (Select All) modes. However, when the command
executes, buildHeadlessCommandContextApi returns an empty
selectedRecords array in exclusion mode because it can't synchronously
resolve record IDs from an "all minus excluded" set. This caused
MergeMultipleRecordsCommand to throw on the empty array guard.
## Fix
Prepended not isSelectAll and to the merge command's conditional
expression, preventing it from appearing when records are selected via
Select All.
Raphaël Bosi
f99c05f0e8