Use char buffer for probeResponse

[thebentern]

While looking at some other memory leak vectors, this one came up as a fairly straightforward change to get rid of another heap allocation

[Copilot]

Pull Request Overview

This PR replaces a dynamic String object with a fixed-size char buffer to address potential memory leak issues in the GPS probing functionality. The change optimizes memory usage by avoiding dynamic allocations during GPS chip detection.

Key changes:

• Replaced dynamic String with fixed 256-byte char buffer
• Implemented manual buffer management with bounds checking
• Updated string operations to use C-style string functions

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[fifieldt]

Back when GPS probe was in its "unreliable" days, we used something similar to this. If this is the way to go (and I do not have anywhere near sufficient C++ knowledge to say one way or another), we must test this incredibly well :)