Fix local cache issue with share_this_page block
Fix local cache issue with share_this_page block

The share_this_page block used to push the services multiple
times to the local "cache" array in case `getSelectedServices()`
was called multiple times.

This fixes the issue by setting the local cache empty every time
the `getSelectedServices()` method gets called.


Former-commit-id: bf6e5641edd79ead063bce8c2168d8fe91f67225
Former-commit-id: df2521f5f1d31999a4b29c072e4ea32b37bec4d6
KorvinSzanto/concrete5,concrete5/concrete5,concrete5/concrete5,olsgreen/concrete5,mlocati/concrete5,haeflimi/concrete5,haeflimi/concrete5,deek87/concrete5,olsgreen/concrete5,mainio/concrete5,rikzuiderlicht/concrete5,haeflimi/concrete5,biplobice/concrete5,mainio/concrete5,a3020/concrete5,MrKarlDilkington/concrete5,mlocati/concrete5,a3020/concrete5,acliss19xx/concrete5,acliss19xx/concrete5,jaromirdalecky/concrete5,MrKarlDilkington/concrete5,KorvinSzanto/concrete5,hissy/concrete5,hissy/concrete5,hissy/concrete5,olsgreen/concrete5,biplobice/concrete5,deek87/concrete5,rikzuiderlicht/concrete5,haeflimi/concrete5,mainio/concrete5,triplei/concrete5-8,deek87/concrete5,rikzuiderlicht/concrete5,jaromirdalecky/concrete5,deek87/concrete5,acliss19xx/concrete5,jaromirdalecky/concrete5,mlocati/concrete5,biplobice/concrete5,biplobice/concrete5,triplei/concrete5-8,MrKarlDilkington/concrete5,jaromirdalecky/concrete5,triplei/concrete5-8,mlocati/concrete5,hissy/concrete5,concrete5/concrete5,KorvinSzanto/concrete5,concrete5/concrete5