refactor: simplify `ViewModels.MergeConflictEditor` #29

Job	Run time
Prepare version string	5s
Build / Build Windows ARM64	3m 26s
Build / Build Linux (arm64)	3m 16s
Build / Build macOS (Apple Silicon)	2m 37s
Build / Build macOS (Intel)	4m 29s
Build / Build Windows x64	3m 16s
Build / Build Linux	3m 15s
Package / Package macOS (osx-arm64)	22s
Package / Package Linux (linux-x64)	54s
Package / Package Windows (win-x64)	35s
Package / Package Windows (win-arm64)	25s
Package / Package macOS (osx-x64)	18s
Package / Package Linux (linux-arm64)	59s
	23m 57s

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