Migrate `logical_plan` tests to `insta`

[blaginin]

In #15178, we're switching hard-coded constants in tests to insta.

This issue targets updating logical_plan tests (datafusion/expr/src/logical_plan).

Examples of tests that need to be switched to insta

• datafusion/datafusion/expr/src/logical_plan/plan.rs

  Lines 4091 to 4104 in 91ad9fd

  	{
  	"Plan": {
  	"Expressions": [
  	"employee_csv.id"
  	],
  	"Node Type": "Projection",
  	"Output": [
  	"id"
  	],
  	"Plans": [
  	{
  	"Condition": "employee_csv.state IN (<subquery>)",
  	"Node Type": "Filter",
  	"Output": [

• datafusion/datafusion/expr/src/logical_plan/builder.rs

  Lines 2348 to 2356 in 91ad9fd

  	let expected = "\
  	Distinct:\
  	\n Union\
  	\n Distinct:\
  	\n Union\
  	\n Distinct:\
  	\n Union\
  	\n TableScan: employee_csv projection=[state, salary]\
  	\n TableScan: employee_csv projection=[state, salary]\

• Debatable, but I think we should also update doc tests, e.g.

  datafusion/datafusion/expr/src/logical_plan/plan.rs

  Lines 1262 to 1265 in 91ad9fd

  	/// assert_eq!(
  	/// "Filter: t1.id = Int32(3)\
  	/// \n TableScan: t1",
  	/// plan.display_indent().to_string()

  - although that said, we should keep doc tests as simple as possible and easy to reproduce for the users. Feel free to write your thoughts on that before submitting the PR so we can discuss it.
  ... and so on - check assert_eq! format!("{plan}"), TableScan:

Check the original issue for tips on how to do the switch and examples of completed PRs.

[Shreyaskr1409]

take