Tune parse nesting limits to mirror those for proto deserialization.

[TristonianJones]

Currently, some of the specified limits for nested expressions within a CEL string exceed the standard proto deserialization limits for Java. There are also other cases where the stated limit exceeds the internal C++ stack recursion limits. These limits should be tuned and reduced to ensure that both proto and the C++ stacks can handle the expression nesting without erroring.