[Tizen.Applications.Common] Replace manual null checks with ArgumentNullException.ThrowIfNull()

[JoonghyunCho]

Closes #7548

Summary

Converts 11 manual 4-line null-check patterns in Tizen.Applications.Common to ArgumentNullException.ThrowIfNull() (.NET 6+ API).

Before (repeated pattern):

if (value == null)
{
    throw new ArgumentNullException(nameof(value));
}

After:

ArgumentNullException.ThrowIfNull(value);

Files Changed

File	Occurrences
Application.cs	1 (args)
ApplicationManager.cs	1 (caller)
ReceivedAppControl.cs	1 (replyRequest)
CoreApplication.cs	2 (runner)
CoreTask.cs	2 (runner)
Bundle.cs	4 (handle, value ×2, argv)

Excluded (non-conforming patterns — extra constructor arguments or non-null conditions):

• Bundle.cs line 75: ArgumentNullException(nameof(handle), "handle is invalid") — extra message
• Bundle.cs line 86: ArgumentNullException(nameof(handle), e.Message) — extra message
• AppControl.cs: extra constructor arguments

Impact

• 6 files changed: -44 lines / +11 lines (net -33)
• No public API changes; behavior preserved (ThrowIfNull is functionally equivalent)
• Build: 0 errors, 4 pre-existing warnings (unchanged)

Benchmark

Device benchmark skipped — no sdb target available in build environment.