Extend TernaryOperatorsShouldNotBeNested to support null safe switch expressions

What problem are you trying to solve?

switch(null) is not supported before Java 18. Adding it to this recipe when using java 18 might be a useful extension.

Describe the solution you'd like

"""
  import java.util.Objects;
  class Test {
    public String determineSomething(String a, String b) {
      return Objects.equals(a, "a") ? "a" : Objects.equals(a, "b") ? b : "nope";
    }
  }
  """,
"""
  class Test {
    public String determineSomething(String a, String b) {
      return switch (a) {
          case "a" -> "a";
          case "b" -> b;
          case null -> "nope";
          default -> "nope";
      };
    }
  }
  """

Start by locating the TernaryOperatorsShouldNotBeNested recipe and its existing tests. Review how the recipe handles nested ternaries, then use the Java 18 example in this issue to define the null-safe switch-expression case. Done means the recipe recognizes this pattern and the relevant tests cover the expected transformation.