bug: HTTPRoute priority ignored

### Current Behavior

I have an incoming HTTP-request which matches both of the following Gateway API HttpRoutes:

```
apiVersion: gateway.networking.k8s.io/v1
kind: HTTPRoute
metadata:
name: api-route
spec:
parentRefs:
- namespace: apisix
name: apisix
rules:
- matches:
- path:
type: PathPrefix
value: /myservice
backendRefs:
- name: myservice
port: 80
filters:
- type: ExtensionRef
extensionRef:
group: apisix.apache.org
kind: PluginConfig
name: api-plugin-config

---

apiVersion: gateway.networking.k8s.io/v1
kind: HTTPRoute
metadata:
name: html-route
spec:
parentRefs:
- namespace: apisix
name: apisix
rules:
- matches:
- method: GET
path:
type: RegularExpression
value: ^/myservice/.*/ws_html
backendRefs:
- name: myservice
port: 80
filters:
- type: ExtensionRef
extensionRef:
group: apisix.apache.org
kind: PluginConfig
name: html-plugin-config
```

Even so the second route (html-route) has a higher priority in the resulting APISIX admin-api routes (due to the "method: GET" restriction), the first route (api-route) always takes precedence. I basically have no way to use the priority field to change which route should be used first, because the priority is not taken into account. Even setting a priority via CRD ApisixRoute or CRD HTTPRoutePolicy has no effect.

The issue is, that api-route results in the admin API in a route with specific uris, while the html-route results in a route with a less specific uri. This makes the priority field never come into play in the APISIX data-plane.

```
{
"service_id": "39186ba5",
"uris": [
"/myservice",
"/myservice/*"
],
"id": "4e3ab1d8",
"name": "mynamespace_api-route_0-0",
"priority": 47429191680,
"labels": {
...
},
"status": 1,
"modifiedIndex": 1788800112427
},
{
"vars": [
[
"uri",
"~~",
"^/myservice/.*/ws_html"
]
],
"name": "mynamespace_html-route_0-0",
"labels": {
...
},
"status": 1,
"modifiedIndex": 1788959573399,
"service_id": "a93412a2",
"uris": [
"/*"
],
"id": "b1ab2f11",
"methods": [
"GET"
],
"priority": 47433385984
}
```

### Expected Behavior

Since Gateway API does not define the priority of RegexExpression path-matches, I would at least want to be able to use the priority field to define the order.
This would be possible if the PrefixPath path-matches would be transformed to APISIX routes in the same way as the RegexExpression path-matches (with uri "/*" and a vars field for matching the prefix). This would then make it necessary for PrefixPath matching rules to include the prefix-length into the priority calculation.

Actually the APISIX Ingress-Controller priority calculation function has a comment which links to the [calculation function of the kong ingress controller](https://github.com/Kong/kubernetes-ingress-controller/blob/57472721319e2c63e56cb8540425257e8e02520f/internal/dataplane/translator/subtranslator/httproute_atc.go#L279-L296) which does exactly this.

Also Kong considers RegexExpression path-matches to always be more important than PrefixPath path-matches, which makes sense, because usually one chooses the easier PrefixPath setup and only in very special cases switches to the more complicated RegexExpression.

### Error Logs

_No response_

### Steps to Reproduce

- Setup two GatewayAPI HTTPRoutes as above which can be matched by the same request uri.
- Confirm the RegexExpression route has the higher priority value in the resulting APISIX routes config. (Checked via the API, e.g. http://localhost:9180/apisix/admin/configs)
- Send a request which matches both routes.
- The request will take the APISIX route which has a lower value in its priority field.
- There is currently no way via Gateway API to make it use the other route, also not by changing the route-priority using ApisixRoute or HTTPRoutePolicy.

### Environment

- APISIX Ingress controller version: apache/apisix-ingress-controller:2.2.0
- Kubernetes cluster version: v1.35.7-gke.1150000

Reproduce the two Gateway API HTTPRoutes and inspect the generated APISIX admin API route configuration, especially the priority calculation and URI/vars representation. Compare the controller's priority calculation with the linked Kong implementation; done means overlapping PrefixPath and RegularExpression matches honor the configured priority and requests select the intended route.

Written by the indexing model from the issue text.