Add missing tabs to org projects page (#22705) (#23412)

Backport #22705 by @yp05327

Fixes https://github.com/go-gitea/gitea/issues/22676

Context Data `IsOrganizationMember` and `IsOrganizationOwner` is used to
control the visibility of `people` and `team` tab.

https://github.com/go-gitea/gitea/blob/2871ea08096cba15546f357d0ec473734ee9d8be/templates/org/menu.tmpl#L19-L40

And because of the reuse of user projects page, User Context is changed
to Organization Context. But the value of `IsOrganizationMember` and
`IsOrganizationOwner` are not being given.

I reused func `HandleOrgAssignment` to add them to the ctx, but may have
some unnecessary variables, idk whether it is ok.

I found there is a missing `PageIsViewProjects` at create project page.

Co-authored-by: yp05327 <576951401@qq.com>

services/context/user.go

@@ -8,7 +8,6 @@ import (
 	"net/http"
 	"strings"
 
-	org_model "code.gitea.io/gitea/models/organization"
 	user_model "code.gitea.io/gitea/models/user"
 	"code.gitea.io/gitea/modules/context"
 )
@@ -57,14 +56,6 @@ func userAssignment(ctx *context.Context, errCb func(int, string, interface{}))
 			} else {
 				errCb(http.StatusInternalServerError, "GetUserByName", err)
 			}
-		} else {
-			if ctx.ContextUser.IsOrganization() {
-				if ctx.Org == nil {
-					ctx.Org = &context.Organization{}
-				}
-				ctx.Org.Organization = (*org_model.Organization)(ctx.ContextUser)
-				ctx.Data["Org"] = ctx.Org.Organization
-			}
 		}
 	}
 }