[GH-16199] add IsValid to model OpenDialogRequest (#26526)

* [GH-16199] add IsValid to model OpenDialogRequest

* [GH-16199] add IsValid to model OpenDialogRequest, revert remove of translations

* [GH-16199] fix tests after revert

* [GH-16199] add IsValid to model OpenDialogRequest

* [GH-16199] revert validation of icon url

* [GH-16199] update go sum

* [GH-16199] log warning for invalid dialog

* [GH-16199] log error for invalid dialog

* [GH-16199] log warning for invalid dialog

* [GH-16199] fix golang-ci

---------

Co-authored-by: Lukas Eipert <git@leipert.io>
Co-authored-by: Mattermost Build <build@mattermost.com>

server/public/go.sum

@@ -77,8 +77,12 @@ github.com/gorilla/websocket v1.5.1 h1:gmztn0JnHVt9JZquRuzLw3g4wouNVzKL15iLr/zn/
 github.com/gorilla/websocket v1.5.1/go.mod h1:x3kM2JMyaluk02fnUJpQuwD2dCS5NDG2ZHL0uE0tcaY=
 github.com/gregjones/httpcache v0.0.0-20180305231024-9cad4c3443a7/go.mod h1:FecbI9+v66THATjSRHfNgh1IVFe/9kFxbXtjV0ctIMA=
 github.com/grpc-ecosystem/grpc-gateway v1.5.0/go.mod h1:RSKVYQBd5MCa4OVpNdGskqpgL2+G+NZTnrVHpWWfpdw=
+github.com/hashicorp/errwrap v1.0.0 h1:hLrqtEDnRye3+sgx6z4qVLNuviH3MR5aQ0ykNJa/UYA=
+github.com/hashicorp/errwrap v1.0.0/go.mod h1:YH+1FKiLXxHSkmPseP+kNlulaMuP3n2brvKWEqk/Jc4=
 github.com/hashicorp/go-hclog v1.6.2 h1:NOtoftovWkDheyUM/8JW3QMiXyxJK3uHRK7wV04nD2I=
 github.com/hashicorp/go-hclog v1.6.2/go.mod h1:W4Qnvbt70Wk/zYJryRzDRU/4r0kIg0PVHBcfoyhpF5M=
+github.com/hashicorp/go-multierror v1.1.1 h1:H5DkEtf6CXdFp0N0Em5UCwQpXMWke8IA0+lD48awMYo=
+github.com/hashicorp/go-multierror v1.1.1/go.mod h1:iw975J/qwKPdAO1clOe2L8331t/9/fmwbPZ6JB6eMoM=
 github.com/hashicorp/go-plugin v1.6.0 h1:wgd4KxHJTVGGqWBq4QPB1i5BZNEx9BR8+OFmHDmTk8A=
 github.com/hashicorp/go-plugin v1.6.0/go.mod h1:lBS5MtSSBZk0SHc66KACcjjlU6WzEVP/8pwz68aMkCI=
 github.com/hashicorp/yamux v0.1.1 h1:yrQxtgseBDrq9Y652vSRDvsKCJKOUD+GzTS4Y0Y8pvE=