Refactor to inline the isNewInTaskView argument.

The local boolean variable isNewInTaskView was only used to pass a value
to the prepareOpenAnimation method. Depending on the conditional branch,
this value was always either true or false.

This change removes the temporary variable and inlines the boolean
literal directly into the method call. This is a pure refactoring that
simplifies the code and improves readability without altering behavior.

Bug: 387193964
Flag: EXEMPT PURE_REFACTOR
Test: atest WMShellUnitTests:TaskViewTransitionsTest
Test: atest WMShellUnitTests:TaskViewTransitionStartAnimationTest
Change-Id: Ic67a25d12d4288ef2d1aa9abf07bea1e3d052dab