[KYUUBI #6550] Delete updateStrategy.rollingUpdate.maxUnavailable because it is alpha feature

# 🔍 Description

StatefulSet's `updateStrategy.rollingUpdate.maxUnavailable` is being used, but this feature is still in the alpha stage. It should not be used by default.

https://kubernetes.io/docs/reference/command-line-tools-reference/feature-gates/#feature-gates-for-alpha-or-beta-features:~:text=%E2%80%93-,MaxUnavailableStatefulSet,-false

https://kubernetes.io/blog/2022/05/27/maxunavailable-for-statefulset/

## Issue References 🔗

None

## Describe Your Solution 🔧

I simply removed it. The behavior should not change even after the removal.

## Types of changes 🔖

- [ ] Bugfix (non-breaking change which fixes an issue)
- [ ] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing functionality to change)

## Test Plan 🧪

#### Behavior Without This Pull Request ⚰️

#### Behavior With This Pull Request 🎉

#### Related Unit Tests

---

# Checklist 📝

- [ ] This patch was not authored or co-authored using [Generative Tooling](https://www.apache.org/legal/generative-tooling.html)

**Be nice. Be informative.**

Closes #6550 from be-hase/polish-updateStrategy.

Closes #6550

ab31779fd [ryosuke-hasebe] Delete updateStrategy.rollingUpdate.maxUnavailable because it is alpha feature

Authored-by: ryosuke-hasebe <ryosuke.hasebe@linecorp.com>
Signed-off-by: Cheng Pan <chengpan@apache.org>

charts/kyuubi/values.yaml

@@ -39,7 +39,6 @@ revisionHistoryLimit: 10
 updateStrategy:
   type: RollingUpdate
   rollingUpdate:
-    maxUnavailable: 1
     partition: 0
 
 image: