Deploy FlexRAN 21.07 on StarlingX in StarlingX has a duplicated command in block of code

This bug tracker is for errors with the documentation, use the following as a template and remove or add fields as you see fit. Convert [ ] into [x] to check boxes:

- [x] This doc is inaccurate in this way: duplicated command in block of code
- [ ] This is a doc addition request.
- [ ] I have a fix to the document that I can paste below including example: input and output.

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-----------------------------------
Release: on 2023-10-05 22:22:32
SHA:
Source: /sample_apps/flexran/deploy-flexran-2107-on-starlingx-c4efa00b1b98.rst
URL: https://docs.starlingx.io/sample_apps/flexran/deploy-flexran-2107-on-starlingx-c4efa00b1b98.html

-----------------------------------

Brief Description
-----------------
In section "FlexRAN build preparation" there is a duplicated command "kubectl create -f volume-ceph.yaml" in this block of code:

```
cat > volume-ceph.yaml << 'EOF'
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: flexran-storage
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 80Gi
  storageClassName: general
EOF

kubectl create -f volume-ceph.yaml

kubectl create -f volume-ceph.yaml
persistentvolumeclaim/flexran-storage created
controller-0:~$ kubectl get pvc
NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE
flexran-storage Bound pvc-43e50806-785f-440b-8ed2-85bb3c9e8f79 80Gi RWO general 9s
```

Severity
--------
Provide the severity of the defect.
<Minor: System/Feature is usable with minor issue>

Steps to Reproduce
------------------
1 - go to URL
2 - go to section "FlexRAN build preparation"
3 - check that the first block of code has a duplicated command

Expected Behavior
------------------
no duplication

Actual Behavior
----------------
duplicated command

Reproducibility
---------------
Reproducible

System Configuration
--------------------
N/A

Branch/Pull Time/Commit
-----------------------
N/A

Last Pass
---------
N/A

Timestamp/Logs
--------------
N/A

Test Activity
-------------
N/A

Workaround
----------
N/A