test(ui): activate app after launch in calibration UI tests

testCalibrationDashboardOpensAndCanGenerate failed in every full-suite
gate run while passing standalone: without an explicit activate() the
synthesized btnCalGenerate click was consumed by window activation when
focus sat on another app after the prior test app terminated. Matches
the launchApp() convention used by the other UI suites.

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Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

Tests/ICCeryUITests/Milestone6CalibrationUITests.swift

@@ -32,6 +32,7 @@ final class Milestone6CalibrationUITests: XCTestCase {
             "ICCERY_TEST_WORKDIR": testWorkDir.path
         ]
         app.launch()
+        app.activate()
     }
 
     override func tearDown() async throws {
@@ -104,6 +105,7 @@ final class Milestone6CalibrationUITests: XCTestCase {
         app.launchEnvironment["ICCERY_TEST_ROOT"] = testRoot.path
         app.launchEnvironment["ICCERY_MOCK_TARGEN_EXIT"] = "2"
         app.launch()
+        app.activate()
 
         let calButton = app.buttons["btnCalibratePrinter"]
         XCTAssertTrue(calButton.waitForExistence(timeout: 10))