Base path handling in HTMX 4 differs from HTMX 2

I don't know if the following is intended behaviour or a regression. I've found that HTMX 4 differs in its handling of `` to HTMX 2 (and it's a bit annoying, tbh).

When I add `hx-post=""` to an element HTMX 2 will send the request to the current URL, HTMX 4 will only send it to the current URL if there is no `` defined. If there is, then HTMX 4 will send the request instead to the base path.

Here's a minimal reproducible example:

- index.html

```html

HTMX test

```

- main.go

```go
package main

import (
"html/template"
"io"
"log"
"net/http"
)

func main() {
http.HandleFunc("GET /test", index)
http.HandleFunc("POST /", post)
log.Fatal(http.ListenAndServe(":8765", nil))
}

func index(w http.ResponseWriter, r *http.Request) {
tmpl := template.Must(template.ParseFiles("index.html"))
err := tmpl.Execute(w, nil)
if err != nil {
log.Print(err)
}
}

func post(w http.ResponseWriter, r *http.Request) {
_, err := io.WriteString(w, r.URL.Path)
if err != nil {
log.Print(err)
}
}
```

Navigating to `http://localhost:8765/test` and clicking on the `

Run the minimal reproduction using index.html and main.go, switching between the HTMX 2.0.10 and 4.0.0 script URLs. Compare the request target and decide whether the base-path behavior is intended; done means the behavior is resolved or documented and verified against this example.

Written by the indexing model from the issue text.