Remove weakref usage and revert memory test threshold

Remove weakref.proxy usage in RequestSigner. The weakref was added for
Python 2.6 memory leak prevention and is no longer needed.

Also revert MAX_GROWTH_BYTES from 13MB back to 10MB in
test_resource_leaks.py now that Python 3.14 support is official.

Author: adev-code

botocore/signers.py

@@ -13,7 +13,6 @@
 import base64
 import datetime
 import json
-import weakref
 
 import botocore
 import botocore.auth
@@ -85,8 +84,7 @@ def __init__(
         self._auth_token = auth_token
         self._service_id = service_id
 
-        # We need weakref to prevent leaking memory in Python 2.6 on Linux 2.6
-        self._event_emitter = weakref.proxy(event_emitter)
+        self._event_emitter = event_emitter
 
     @property
     def region_name(self):

tests/functional/leak/test_resource_leaks.py

@@ -22,10 +22,10 @@ class TestDoesNotLeakMemory(BaseClientDriverTest):
     # a substantial amount of time to the total test run time.
     INJECT_DUMMY_CREDS = True
     # We're making up numbers here, but let's say arbitrarily
-    # that the memory can't increase by more than 13MB.
+    # that the memory can't increase by more than 10MB.
 
     # TODO: Attempt to bring this back to 10MB once Python 3.14 releases
-    MAX_GROWTH_BYTES = 13 * 1024 * 1024
+    MAX_GROWTH_BYTES = 10 * 1024 * 1024
 
     def test_create_single_client_memory_constant(self):
         self.cmd('create_client', 's3')