Remove redundant null-forgiving operator on cts in Program.cs

[Copilot]

cts in src/Microsoft.Android.Run/Program.cs is a non-nullable CancellationTokenSource initialized at declaration, making the ! in cts!.Token redundant and a violation of the repo's "never use !" rule.

Change

• src/Microsoft.Android.Run/Program.cs: Remove postfix ! from cts!.Token.IsCancellationRequested → cts.Token.IsCancellationRequested

// Before
while (!cts!.Token.IsCancellationRequested) {

// After
while (!cts.Token.IsCancellationRequested) {

[Copilot]

Pull request overview

Removes an unnecessary null-forgiving operator in Microsoft.Android.Run where cts is already a non-nullable CancellationTokenSource initialized at declaration, aligning the code with the repo’s “never use !” guidance.

Changes:

• Replace cts!.Token.IsCancellationRequested with cts.Token.IsCancellationRequested in the logcat/app-exit wait loop.