Improve bg95 connection speed by only setting nwscanseq if needed

[scott-brust]

Problem

On warm boot, msom/BG95-M5 platforms consistently experience a dregistration event 18 seconds after boot. This causes the ongoing PPP link / server socket to fail and cellular registration to start over. This increases time for the platform to come online

Solution

The nwscanseq setting is being set on every boot, which triggers the network de-registration. This should only be set when needed. The network scan order should be LTE > 2G > NBIOT. We cannot specifically exclude NBIOT with the nwscanseq command. NBIOT will be excluded in the iotopmode command

Steps to Test

Run this branch. Let modem register on network. Press reset button. Device should reconnect to the particle cloud around 10 seconds. It should not be deregistered from the cell network

Example App

any

References

slack discussion

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Completeness

• User is totes amazing for contributing!
• Contributor has signed CLA (Info here)
• Problem and Solution clearly stated
• Run unit/integration/application tests on device
• Added documentation
• Added to CHANGELOG.md after merging (add links to docs and issues)