Fix CI compilation errors by converting arrays to lists for String.concat

- Fixed type compatibility issues where Commands.executeProcess returns string arrays but String.concat expects string lists
- Added List.ofArray conversions to handle the array-to-list type mismatch
- Build verification and error handling now work correctly with proper type conversions

Co-authored-by: T-Gro <[email protected]>

Author: Copilot

tests/FSharp.Compiler.ComponentTests/CompilerCompatibilityTests.fs

@@ -22,15 +22,15 @@ type CompilerCompatibilityTests() =
         let (exitCode, output, error) = Commands.executeProcess "dotnet" args projectPath
 
         if exitCode <> 0 then
-            let outputStr = String.concat "\n" output
-            let errorStr = String.concat "\n" error
+            let outputStr = String.concat "\n" (List.ofArray output)
+            let errorStr = String.concat "\n" (List.ofArray error)
             failwith $"Build failed with exit code {exitCode}. Output: {outputStr}. Error: {errorStr}"
 
-        String.concat "\n" output
+        String.concat "\n" (List.ofArray output)
 
     let runApp appBinaryPath =
         let (exitCode, output, error) = Commands.executeProcess "dotnet" appBinaryPath (Path.GetDirectoryName(appBinaryPath))
-        (exitCode, String.concat "\n" output, String.concat "\n" error)
+        (exitCode, String.concat "\n" (List.ofArray output), String.concat "\n" (List.ofArray error))
 
     let cleanBinObjDirectories projectPath =
         let binPath = Path.Combine(projectPath, "bin")