[FIX] sap.ui.table.Table: fixedColumnCount calculation with hidden columns in aggregation
[FIX] sap.ui.table.Table: fixedColumnCount calculation with hidden columns in aggregation

- fixes an issue where a column could not be set as a fixed column if there were hidden columns
in the aggregation.

Change-Id: I4d1fb9bd2d8db77d7ce873f1844be45827f54bab
BCP: 1680143496

cschuff/openui5,SAP/openui5,cschuff/openui5,olirogers/openui5,SQCLabs/openui5,SAP/openui5,olirogers/openui5,SQCLabs/openui5,SAP/openui5,nzamani/openui5,olirogers/openui5,nzamani/openui5,cschuff/openui5,SAP/openui5,nzamani/openui5,SQCLabs/openui5