`IfElseIfConstructToSwitch` fails to add variable declarations for custom types used in `instanceof`

[timtebeek]

• Following Fix IfElseIfConstructToSwitch type attribution for non-JDK types #994
• We saw https://github.com/moderneinc/rewrite-migrate-kotlin/commit/4a05bb4d6959fa7196176f4597536d2030aba36f#diff-d0136ee922ed73e329538416ecf67d2e45a4b3d8a63287b96e6fb8b0975c2e30 introduce missing variables in cases
  
• Fixed manually in https://github.com/moderneinc/rewrite-migrate-kotlin/commit/e73206c3f15af367dd640c07abc12000ce76baf0