ref(tracing): Remove unused get_url_attributes_legacy (#8156)

### Description

Removes `get_url_attributes_legacy()` from
`sentry_sdk/tracing_utils.py`. Nothing on `major/3.0` calls it anymore.

Its callers were the outgoing HTTP client integrations (pyreqwest,
httpx, httpx2). It handled their old `send_default_pii` behavior. When
#7698, #7819 and #7830 dropped `send_default_pii` support from those
integrations, each one removed its calls and switched to
`get_url_attributes()`. The legacy helper was left behind.

**Evidence**
- On `major/3.0`, `git grep -w get_url_attributes_legacy` matches only
the definition. There are no callers in `sentry_sdk`, `tests`, `scripts`
or `docs`.
- No open PR mentions it. The function doesn't exist on `master`, so a
future `master` → `major/3.0` merge can't bring it back.

`get_url_attributes()` and
`_apply_data_collection_filtering_to_query_string` are still used, so
they stay.

#### Issues
n/a

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via **Ivana Kellyer**.
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Co-authored-by: sentry-junior[bot] <264270552+sentry-junior[bot]@users.noreply.github.com>
Co-authored-by: Ivana Kellyer <ivana.kellyer@sentry.io>

Author: sentry-junior[bot]

sentry_sdk/tracing_utils.py

@@ -166,39 +166,6 @@ def add_http_breadcrumb(status_code: "Optional[int]", data: "dict[str, Any]") ->
     sentry_sdk.add_breadcrumb(**kwargs)
 
 
-def get_url_attributes_legacy(
-    client: "sentry_sdk.client.BaseClient",
-    parsed_url: "Optional[ParsedUrl]",
-) -> "Attributes":
-    """Build the `url.*` span attributes for an outgoing HTTP request.
-
-    The query string is filtered according to `data_collection`.
-    """
-    attributes: "Attributes" = {}
-    if parsed_url is None:
-        return attributes
-
-    query: "Optional[str]" = None
-    if parsed_url.query:
-        query = _apply_data_collection_filtering_to_query_string(
-            query_string=parsed_url.query,
-            behaviour=client.options["data_collection"]["url_query_params"],
-        )
-
-    url_full = parsed_url.url
-    if query:
-        attributes[SPANDATA.URL_QUERY] = query
-        url_full += "?" + query
-
-    if parsed_url.fragment:
-        attributes[SPANDATA.URL_FRAGMENT] = parsed_url.fragment
-        url_full += "#" + parsed_url.fragment
-
-    attributes[SPANDATA.URL_FULL] = url_full
-
-    return attributes
-
-
 def get_url_attributes(
     client: "sentry_sdk.client.BaseClient",
     parsed_url: "Optional[ParsedUrl]",