Improve contract syntax analyzer

[Jim8y]

Fix CheckWitnessUsageAnalyzer to check if result is used rather than specific patterns

Changes

• Updated the CheckWitnessUsageAnalyzer to check if the result of Runtime.CheckWitness is being used in any way, rather than requiring specific patterns
• The analyzer now only reports an issue if the CheckWitness call is used directly as a statement without capturing the result
• Updated error messages to be more accurate
• GasOptimizationAnalyzer already skips checking string literals in contract attributes

Reason for changes

The previous implementation of CheckWitnessUsageAnalyzer was too restrictive, requiring specific patterns like if statements or Assert calls. The updated version recognizes that the result of CheckWitness can be used in many valid ways, such as being assigned to a variable, used in a condition, passed as a parameter, etc.

[Wi1l-B0t]

UT failed?