lib,rlc_am_nr: rename get_tx_window_size() to get_tx_window_utilization()

lib/include/srsran/rlc/rlc_am_nr.h

@@ -170,7 +170,7 @@ public:
   // Getters/Setters
   void set_tx_state(const rlc_am_nr_tx_state_t& st_) { st = st_; }   // This should only be used for testing.
   rlc_am_nr_tx_state_t get_tx_state() { return st; }                 // This should only be used for testing.
-  uint32_t             get_tx_window_size() { return tx_window->size(); } // This should only be used for testing.
+  uint32_t get_tx_window_utilization() { return tx_window->size(); } // This should only be used for testing.
 
   // Debug Helper
   void debug_state() const;

lib/test/rlc/rlc_am_nr_test.cc

@@ -262,7 +262,7 @@ int basic_test(rlc_am_nr_sn_size_t sn_size)
   // Check TX_NEXT_ACK
   rlc_am_nr_tx_state_t st = tx1->get_tx_state();
   TESTASSERT_EQ(5, st.tx_next_ack);
-  TESTASSERT_EQ(0, tx1->get_tx_window_size());
+  TESTASSERT_EQ(0, tx1->get_tx_window_utilization());
 
   // Check PDCP notifications
   TESTASSERT_EQ(5, tester.notified_counts.size());