disable istio provisioner by default

[medyagh]

replaces this #6272

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: medyagh

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[sharifelgamal]

/ok-to-test

[codecov-io]

Codecov Report

Merging #6315 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #6315   +/-   ##
=======================================
  Coverage   38.23%   38.23%           
=======================================
  Files         123      123           
  Lines        8269     8269           
=======================================
  Hits         3162     3162           
  Misses       4696     4696           
  Partials      411      411

Impacted Files	Coverage Δ
pkg/minikube/assets/addons.go	37.93% <ø> (ø)	⬆️

[minikube-bot]

All Times minikube: [ 125.206221 123.431655 113.351792]
All Times Minikube (PR 6315): [ 124.154944 122.623291 124.311129]

Average minikube: 120.663223
Average Minikube (PR 6315): 123.696455

Averages Time Per Log

+----------------------+-----------+--------------------+
|         LOG          | MINIKUBE  | MINIKUBE (PR 6315) |
+----------------------+-----------+--------------------+
| minikube v           |  0.228835 |           0.223332 |
| Creating kvm2        | 46.509110 |          46.324093 |
| Preparing Kubernetes | 48.018393 |          51.626834 |
| Pulling images       |  2.965834 |           2.923849 |
| Launching Kubernetes | 20.150965 |          19.986949 |
| Waiting for cluster  |  2.738554 |           2.559944 |
| Done                 |           |                    |
|                      |  0.051108 |           0.051453 |
+----------------------+-----------+--------------------+