update string deserializer

[carsonloyaltrimble]

Proposed change(s)

Updated the String deserialization from ROS2 to check for valid string length

Useful links (GitHub issues, JIRA tickets, forum threads, etc.)

Provide any relevant links here.

Types of change(s)

• Bug fix
• New feature
• Code refactor
• Documentation update
• Other (please describe)

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