fix(inputs.redfish): Add URL and content type to JSON parse error

[skartikey]

Summary

When a Redfish endpoint returns a non-JSON body (for example a BMC serving an HTML web-UI or login page, or a proxy returning an HTML error page), the plugin failed with a bare error parsing input: invalid character '<' looking for beginning of value that did not say which of its several per-gather requests failed or what the body was.

This wraps the parse error with the request URL and the response Content-Type, matching the address-in-error style already used for the status-code check, so the failing request and its actual content type are visible without extra debugging.

Checklist

• No AI generated code was used in this PR
• AI generated code used in this PR follows the InfluxData Policy on AI-Generated Code Contributions

Related issues

related to #19289

[telegraf-tiger]

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armel.deb	armv6hl.rpm	freebsd_amd64.tar.gz	windows_i386.zip
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i386.deb	ppc64le.rpm	freebsd_i386.tar.gz
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s390x.deb		linux_i386.tar.gz
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