Log checkout so SHA is known
Log checkout so SHA is known

This commit changes the task type of the checkoutBwcBranch task to Exec
from LoggedExec so that the output of the checkout command is
shown. This enables us to see the SHA used for the checkout which can be
useful when debugging a BWC break.

Relates #25166

strapdata/elassandra5-rc,strapdata/elassandra5-rc,strapdata/elassandra5-rc,strapdata/elassandra5-rc,strapdata/elassandra5-rc