Use Visible instead of RequiredPolicy for Blazor

[berkansasmaz]

The width and height of the replaced image are almost the same:

Also, maybe we can remove the code block in this section because none of these variables are used.

After this PR is approved, I will update the Commercial documents.

[hikalkan]

policy names are used in the AbpCrudPageBase class:

abp/framework/src/Volo.Abp.BlazoriseUI/AbpCrudPageBase.cs

Lines 235 to 251 in 883b2c7

	protected virtual async Task SetPermissionsAsync()
	{
	if (CreatePolicyName != null)
	{
	HasCreatePermission = await AuthorizationService.IsGrantedAsync(CreatePolicyName);
	}
	if (UpdatePolicyName != null)
	{
	HasUpdatePermission = await AuthorizationService.IsGrantedAsync(UpdatePolicyName);
	}
	if (DeletePolicyName != null)
	{
	HasDeletePermission = await AuthorizationService.IsGrantedAsync(DeletePolicyName);
	}
	}