Fix #1492: Serialize WithClientIP matcher to Request.ClientIP

[Bafyn]

Problem

When a mapping that uses WithClientIP() is serialized to its MappingModel, the client‑IP matcher is not written to Request.ClientIP. Instead it is written to Request.Path.

Root cause

• Serialize - MappingConverter.ToMappingModel assigned the client-IP matchers to mappingModel.Request.Path.
• Deserialize - WireMockServer.ConvertMapping.InitRequestBuilder rebuilt the object-form Request.ClientIP via WithPath() instead of WithClientIP().

References

Fixes #1492

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