Built-in examples are replaced by generated ones in Cloud Shell

Previously, changes on core are made to incorporate `azext_ai_examples`:

- `azext_ai_examples` is always loaded: https://github.com/Azure/azure-cli/pull/13294
- `azext_ai_examples` hooks into `azure-cli-core` to modify the built-in examples: https://github.com/Azure/azure-cli/pull/10987

In Cloud Shell, `azext_ai_examples` is pre-installed. It replaces built-in hand-crafted high-qualify large-quantity examples with auto-generated low-quality small-quantity examples.

For example, for `az vm create --help`:

Cloud Shell:

```
Examples
Create an Azure Virtual Machine. (autogenerated)
az vm create --admin-username deploy --generate-ssh-keys --image Centos --name MyVm
--resource-group MyResourceGroup

Create a default Ubuntu VM with automatic SSH authentication.
az vm create --name MyVm --resource-group MyResourceGroup --image UbuntuLTS

Create a VM by attaching to a managed operating system disk.
az vm create --resource-group MyResourceGroup --name MyVm --attach-os-disk MyOsDisk --os-
type linux

Create an Ubuntu Linux VM using a cloud-init script for configuration. See:
https://docs.microsoft.com/azure/virtual-machines/virtual-machines-linux-using-cloud-init.
az vm create --resource-group MyResourceGroup --name MyVm --image debian --custom-data
MyCloudInitScript.yml

Create a default Windows Server VM with a private IP address.
az vm create --name MyVm --resource-group MyResourceGroup --public-ip-address "" --image
Win2012R2Datacenter
```
Some examples are even wrong:

- This link returns 404: https://docs.microsoft.com/azure/virtual-machines/virtual-machines-linux-using-cloud-init

Locally:

```
Examples
Create a default Ubuntu VM with automatic SSH authentication.
az vm create -n MyVm -g MyResourceGroup --image UbuntuLTS

Create a default RedHat VM with automatic SSH authentication using an image URN.
az vm create -n MyVm -g MyResourceGroup --image RedHat:RHEL:7-RAW:7.4.2018010506

Create a default Windows Server VM with a private IP address.
az vm create -n MyVm -g MyResourceGroup --public-ip-address "" --image Win2012R2Datacenter

Create a VM from a custom managed image.
az vm create -g MyResourceGroup -n MyVm --image MyImage

Create a VM from a generalized gallery image version.
az vm create -g MyResourceGroup -n MyVm --image /subscriptions/00000000-0000-0000-0000-00000
0000000/resourceGroups/myRG/providers/Microsoft.Compute/galleries/myGallery/images/myImage/v
ersions/1.0.0

Create a VM from a specialized gallery image version.
az vm create -g MyResourceGroup -n MyVm --image /subscriptions/00000000-0000-0000-0000-00000
0000000/resourceGroups/myRG/providers/Microsoft.Compute/galleries/myGallery/images/myImage/v
ersions/1.0.0 --specialized

Create a VM from the latest version of a gallery image
az vm create -g MyResourceGroup -n MyVm --image /subscriptions/00000000-0000-0000-0000-00000
0000000/resourceGroups/myRG/providers/Microsoft.Compute/galleries/myGallery/images/myImage

Create a VM by attaching to a managed operating system disk.
az vm create -g MyResourceGroup -n MyVm --attach-os-disk MyOsDisk --os-type linux

Create an Ubuntu Linux VM using a cloud-init script for configuration. See:
https://docs.microsoft.com/azure/virtual-machines/linux/using-cloud-init.
az vm create -g MyResourceGroup -n MyVm --image debian --custom-data MyCloudInitScript.yml

Create a Debian VM with SSH key authentication and a public DNS entry, located on an existing
virtual network and availability set.
az vm create -n MyVm -g MyResourceGroup --image debian --vnet-name MyVnet --subnet subnet1 \
--availability-set MyAvailabilitySet --public-ip-address-dns-name MyUniqueDnsName \
--ssh-key-values @key-file

Create a simple Ubuntu Linux VM with a public IP address, DNS entry, two data disks (10GB and
20GB), and then generate ssh key pairs.
az vm create -n MyVm -g MyResourceGroup --public-ip-address-dns-name MyUniqueDnsName \
--image ubuntults --data-disk-sizes-gb 10 20 --size Standard_DS2_v2 \
--generate-ssh-keys

Create a Debian VM using Key Vault secrets.
az keyvault certificate create --vault-name vaultname -n cert1 \
-p "$(az keyvault certificate get-default-policy)"

secrets=$(az keyvault secret list-versions --vault-name vaultname \
-n cert1 --query "[?attributes.enabled].id" -o tsv)

vm_secrets=$(az vm secret format -s "$secrets")

az vm create -g group-name -n vm-name --admin-username deploy \
--image debian --secrets "$vm_secrets"

Create a CentOS VM with a system assigned identity. The VM will have a 'Contributor' role with
access to a storage account.
az vm create -n MyVm -g rg1 --image centos --assign-identity [system] --scope
/subscriptions/99999999-1bf0-4dda-
aec3-cb9272f09590/MyResourceGroup/myRG/providers/Microsoft.Storage/storageAccounts/storage1

Create a debian VM with a user assigned identity.
az vm create -n MyVm -g rg1 --image debian --assign-identity
/subscriptions/99999999-1bf0-4dda-aec3-cb9272f09590/resourcegroups/myRG/providers/Microsoft.
ManagedIdentity/userAssignedIdentities/myID

Create a debian VM with both system and user assigned identity.
az vm create -n MyVm -g rg1 --image debian --assign-identity [system]
/subscriptions/99999999-1bf0-4dda-aec3-cb9272f09590/resourcegroups/myRG/providers/Microsoft.
ManagedIdentity/userAssignedIdentities/myID

Create a VM in an availability zone in the current resource group's region.
az vm create -n MyVm -g MyResourceGroup --image Centos --zone 1

Create multiple VMs. In this example, 3 VMs are created. They are MyVm0, MyVm1, MyVm2.
az vm create -n MyVm -g MyResourceGroup --image centos --count 3

Create a VM from shared gallery image (private preview feature, please contact shared image
gallery team by email sigpmdev@microsoft.com to register for preview if you're interested in
using this feature).
az vm create -n MyVm -g MyResourceGroup --image
/SharedGalleries/{gallery_unique_name}/Images/{image}/Versions/{version}
```

This impedes Azure CLI's capability in Cloud Shell.