fix(splunk): storage config typo (#21464)

**Description**
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⚒️ Fixes  #21463

**⚙️ Type of change**

- [ ] ⚙️ Feature/App addition
- [x] 🪛 Bugfix
- [ ] ⚠️ Breaking change (fix or feature that would cause existing
functionality to not work as expected)
- [ ] 🔃 Refactor of current code

**🧪 How Has This Been Tested?**
Automated tests only

**📃 Notes:**


**✔️ Checklist:**

- [x] ⚖️ My code follows the style guidelines of this project
- [x] 👀 I have performed a self-review of my own code
- [x] #️⃣ I have commented my code, particularly in hard-to-understand
areas
- [x] 📄 I have made corresponding changes to the documentation
- [x] ⚠️ My changes generate no new warnings
- [x] 🧪 I have added tests to this description that prove my fix is
effective or that my feature works
- [x] ⬆️ I increased versions for any altered app according to semantic
versioning
- [x] I made sure the title starts with `feat(chart-name):`,
`fix(chart-name):` or `chore(chart-name):`

**➕ App addition**

If this PR is an app addition please make sure you have done the
following.

- [ ] 🖼️ I have added an icon in the Chart's root directory called
`icon.png`

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charts/stable/splunk/Chart.yaml

@@ -35,4 +35,4 @@ sources:
   - https://github.com/truecharts/charts/tree/master/charts/stable/splunk
   - https://hub.docker.com/r/splunk/splunk
 type: application
-version: 8.0.4
+version: 8.0.5

charts/stable/splunk/values.yaml

@@ -62,7 +62,7 @@ persistence:
   config:
     enabled: true
     mountPath: /opt/splunk/var
-  datap:
+  data:
     enabled: true
     mountPath: /splunkdata