Implement Control Character Validation in IRI Class

[bivens-dev]

Description

According to RFC 3987 (Internationalized Resource Identifiers), control characters (U+0000 to U+001F, U+007F to U+009F) are not allowed directly within an IRI string (they must be percent-encoded). This issue tracks the implementation of a validation check for control characters in the IRI class of the rdf_dart package.

Goal

The goal of this issue is to implement the _isValidControlCharacters function within the IRI class (lib/src/iri.dart). This function will:

• Examine an IRI string to detect any presence of control characters outside of valid percent-encoded sequences.
• Throw an InvalidIRIException if any such control characters are detected.
• Make sure that the characters TAB, CR and LF are not rejected.

Implementation Notes

• Refer to RFC 3987, Section 2.2 .
• Ensure that control characters within valid percent-encoded sequences (e.g., %00) are not flagged as invalid.
• Ensure that control characters TAB, CR and LF are not rejected.
• Leverage the existing InvalidIRIException for error handling.