[FIX] calendar: attendee of a private event should be able to see the content
[FIX] calendar: attendee of a private event should be able to see the content

Someone invited to an event should be able to see all details, instead of "busy"

This commit closes #12935

NeovaHealth/odoo,OpenUpgrade/OpenUpgrade,datenbetrieb/odoo,synconics/odoo,dfang/odoo,NeovaHealth/odoo,Daniel-CA/odoo,BT-ojossen/odoo,CatsAndDogsbvba/odoo,makinacorpus/odoo,leorochael/odoo,Nowheresly/odoo,glovebx/odoo,Adel-Magebinary/odoo,Daniel-CA/odoo,OpenUpgrade/OpenUpgrade,synconics/odoo,BT-ojossen/odoo,NeovaHealth/odoo,NeovaHealth/odoo,bplancher/odoo,Daniel-CA/odoo,ygol/odoo,dfang/odoo,leorochael/odoo,ygol/odoo,vnsofthe/odoo,CatsAndDogsbvba/odoo,ehirt/odoo,datenbetrieb/odoo,BT-ojossen/odoo,odootr/odoo,leorochael/odoo,tvibliani/odoo,Nowheresly/odoo,Daniel-CA/odoo,alexcuellar/odoo,synconics/odoo,Elico-Corp/odoo_OCB,makinacorpus/odoo,Nowheresly/odoo,laslabs/odoo,NeovaHealth/odoo,ehirt/odoo,datenbetrieb/odoo,Adel-Magebinary/odoo,vnsofthe/odoo,synconics/odoo,spadae22/odoo,alexcuellar/odoo,odootr/odoo,glovebx/odoo,Nowheresly/odoo,makinacorpus/odoo,diagramsoftware/odoo,diagramsoftware/odoo,OpenUpgrade/OpenUpgrade,tvibliani/odoo,NeovaHealth/odoo,bplancher/odoo,Adel-Magebinary/odoo,funkring/fdoo,funkring/fdoo,leorochael/odoo,spadae22/odoo,ygol/odoo,odootr/odoo,CatsAndDogsbvba/odoo,spadae22/odoo,tvibliani/odoo,Adel-Magebinary/odoo,Daniel-CA/odoo,vnsofthe/odoo,ehirt/odoo,alexcuellar/odoo,glovebx/odoo,vnsofthe/odoo,synconics/odoo,makinacorpus/odoo,OpenUpgrade/OpenUpgrade,dfang/odoo,odootr/odoo,OpenUpgrade/OpenUpgrade,vnsofthe/odoo,Nowheresly/odoo,alexcuellar/odoo,Adel-Magebinary/odoo,Daniel-CA/odoo,synconics/odoo,Elico-Corp/odoo_OCB,funkring/fdoo,tvibliani/odoo,OpenUpgrade/OpenUpgrade,odootr/odoo,vnsofthe/odoo,Elico-Corp/odoo_OCB,spadae22/odoo,glovebx/odoo,Adel-Magebinary/odoo,synconics/odoo,makinacorpus/odoo,Elico-Corp/odoo_OCB,CatsAndDogsbvba/odoo,Adel-Magebinary/odoo,hip-odoo/odoo,spadae22/odoo,Elico-Corp/odoo_OCB,hip-odoo/odoo,BT-ojossen/odoo,BT-ojossen/odoo,alexcuellar/odoo,ehirt/odoo,bplancher/odoo,ehirt/odoo,leorochael/odoo,makinacorpus/odoo,diagramsoftware/odoo,leorochael/odoo,datenbetrieb/odoo,tvibliani/odoo,bplancher/odoo,BT-ojossen/odoo,funkring/fdoo,Nowheresly/odoo,glovebx/odoo,leorochael/odoo,dfang/odoo,NeovaHealth/odoo,ygol/odoo,diagramsoftware/odoo,makinacorpus/odoo,OpenUpgrade/OpenUpgrade,CatsAndDogsbvba/odoo,laslabs/odoo,laslabs/odoo,datenbetrieb/odoo,odootr/odoo,glovebx/odoo,laslabs/odoo,CatsAndDogsbvba/odoo,ygol/odoo,bplancher/odoo,glovebx/odoo,datenbetrieb/odoo,tvibliani/odoo,Daniel-CA/odoo,ehirt/odoo,spadae22/odoo,alexcuellar/odoo,vnsofthe/odoo,dfang/odoo,CatsAndDogsbvba/odoo,diagramsoftware/odoo,tvibliani/odoo,funkring/fdoo,hip-odoo/odoo,hip-odoo/odoo,datenbetrieb/odoo,dfang/odoo,ygol/odoo,funkring/fdoo,Elico-Corp/odoo_OCB,laslabs/odoo,ygol/odoo,hip-odoo/odoo,bplancher/odoo,laslabs/odoo,diagramsoftware/odoo,ehirt/odoo,diagramsoftware/odoo,spadae22/odoo,Nowheresly/odoo,odootr/odoo,funkring/fdoo,BT-ojossen/odoo,alexcuellar/odoo,hip-odoo/odoo