Added heart rate to Spezi HealthKit (#2)

# Added heart rate to Spezi HealthKit

## ♻️ Current situation & Problem
- We didn't collect heart rate.


## ⚙️ Release Notes 
- Added heart rate to Spezi HealthKit


## 📚 Documentation
- We didn't add any new documentation.


## ✅ Testing
- No tests added.


## 📝 Code of Conduct & Contributing Guidelines 

By submitting creating this pull request, you agree to follow our [Code
of
Conduct](https://github.com/CS342/.github/blob/main/CODE_OF_CONDUCT.md)
and [Contributing
Guidelines](https://github.com/CS342/.github/blob/main/CONTRIBUTING.md):
- [x] I agree to follow the [Code of
Conduct](https://github.com/CS342/.github/blob/main/CODE_OF_CONDUCT.md)
and [Contributing
Guidelines](https://github.com/CS342/.github/blob/main/CONTRIBUTING.md).

Author: PSchmiedmayer

CS342ExampleApplication/CS342ExampleApplicationDelegate.swift

@@ -83,6 +83,10 @@ class CS342ExampleApplicationDelegate: SpeziAppDelegate {
 
     private var healthKit: HealthKit {
         HealthKit {
+            CollectSample(
+                HKQuantityType(.heartRate),
+                deliverySetting: .anchorQuery(.automatic)
+            )
             CollectSample(
                 HKQuantityType(.stepCount),
                 deliverySetting: .anchorQuery(.automatic)