Fixed error handling for NRF_ERROR_RESOURCES

[sorceressofmathematics]

Whenever a NRF_ERROR_RESOURCES was encountered, the error-handling code in the BLEAdapter was searching for the string "Error code: 19" even though this string is no longer contained within the exception. Because of this, these were never getting handled and the program simply crashed instead, including when using nrfutil's DFU functionality. I've fixed the code in question so it should be handling these errors correctly again.

[CLAassistant]

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[bihanssen]

@sorceressofmathematics thanks for reporting and providing a PR. If you sign the CLA we can merge it in.

[sorceressofmathematics]

Just signed it, thanks.

[bihanssen]

@sorceressofmathematics CLAassistant seems to complain about CLA signing still.