Remove misleading documentation on Java support in core-tools

[This document](https://learn.microsoft.com/en-us/azure/azure-functions/functions-run-local?tabs=windows%2Cisolated-process%2Cnode-v4%2Cpython-v2%2Chttp-trigger%2Ccontainer-apps&pivots=programming-language-java) is misleading. Java is not supported in core-tools (see [here](https://github.com/Azure/azure-functions-core-tools/issues/2542#issuecomment-819087029) and see [supported local development environments](https://learn.microsoft.com/en-us/azure/azure-functions/functions-develop-local?pivots=programming-language-java#local-development-environments)). While a core-tools installation is necessary for these environments, it should not be used directly.

Additionally, instructions in this doc such as `func new --template "Http Trigger" --name MyHttpTrigger` are not supported and will result in errors.

This issue tracks the removal of the misleading doc.

Start with the linked Microsoft documentation, the referenced core-tools discussion, and the supported local development environments page. Locate where the Java guidance and `func new --template "Http Trigger" --name MyHttpTrigger` example are maintained. Done means the misleading support claims and unsupported command instructions are removed or corrected.

Written by the indexing model from the issue text.