net-mgmt/nrpe: allow hostnames in allowed_hosts

[bkmorale]

Important notices
Before you submit a pull request, we ask you kindly to acknowledge the following:

• [X ] I have read the contributing guide lines at https://github.com/opnsense/plugins/blob/master/CONTRIBUTING.md
• [X ] I opened an issue first for non-trivial changes and linked it below.
• NRPE Plugin doesn't allow for DNS in allowed hosts #4932
• [X ] AI tools were used to create at least part of the code submitted herewith.

If AI was used, please disclose:

• Model used: Gemni 3
• Extent of AI involvement:
• Helped to locate allowed_host entry and General.xml file in src

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Related issue
If this pull request relates to an issue, link it here:
#4932

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Describe the problem
I have noticed that when using NRPE in opnsense I am unable to add an allowed host that is a DNS entry and provides the error "Please specify a valid network segment or IP address." the current workaround I have is to manually update the nrpe file and add the DNS in the config file. the plugin will then work as expected but will break should anyone make changes to the NRPE config in the opnsense UI.

I have done this with existing servers in production and with newly deployed systems along with lab systems, I can confirm this is applicable to anything on version OPNsense 25.7.0 and above

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Describe the proposed solution
Updated the General.xml to allow hostname entries in the allowed_host field

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