Given a nested structure composed of Lists and Maps, getByPath will return the value
keyed by path. getByPath is a method on Lists and Maps.
The path is string Map keys and integer List indices separated by dot. An optional third
argument returns a default value if the path lookup fails due to a missing value.
Eg.
['key0': ['a', 'b'], 'key1': ['c', 'd']].getByPath('key1') = ['c', 'd']
['key0': ['a', 'b'], 'key1': ['c', 'd']].getByPath('key1.0') = 'c'
['key0': ['a', 'b'], 'key1': ['c', 'd']].getByPath('key2', 'x') = 'x'
[['key0': 'value0'], ['key1': 'value1']].getByPath('1.key1') = 'value1'
Throws IllegalArgumentException if an item cannot be found and a default is not given.
Throws NumberFormatException if a path element operating on a List is not an integer.
Fixes#42769
500205e8c5