remove mutability from PropertyOracles #142

Job	Run time
Tests and Analysis (JDK: 11)	12m 34s
Tests and Analysis (JDK: 17)	12m 7s
Tests and Analysis (JDK: 21)	11m 47s
Platform Integration (JDK: 11, OS: ubuntu-latest)	4m 40s
Platform Integration (JDK: 11, OS: windows-latest)	5m 57s
Platform Integration (JDK: 11, OS: macOS-latest)	4m 30s
Platform Integration (JDK: 17, OS: ubuntu-latest)	4m 27s
Platform Integration (JDK: 17, OS: windows-latest)	5m 33s
Platform Integration (JDK: 17, OS: macOS-latest)	4m 18s
Platform Integration (JDK: 21, OS: ubuntu-latest)	4m 31s
Platform Integration (JDK: 21, OS: windows-latest)	5m 18s
Platform Integration (JDK: 21, OS: macOS-latest)	4m 36s
Deploy	6m 36s
Coverage	6m 52s
	1h 33m 46s

Provide feedback