[BUGFIX] Install tool: Warning in upgrade wizard

The 'silent' cache framework table upgrade throws a warning that
explode() expects a string but an array is given in
SqlSchemaMigration getStatementArray(). The upgrade wizard uses
a wrong API call, since this method is already called within
getExpectedDatabaseSchema() of the helper class.

Change-Id: I6cdde020265e730faa07a25ebda41917672ccea7
Resolves: #49265
Related: #49162
Releases: 6.2
Reviewed-on: https://review.typo3.org/21516
Reviewed-by: Christian Kuhn
Tested-by: Christian Kuhn