Only start scan/advertise when host re-synced if duration was indefinite.

Previously when the host reset while scanning (if active prior) it would be restarted automatically.
This caused errors for some applications and has been removed since the event invokes the scan
ended callback for the app to take action. Instead scanning will now only be restarted if the duration
was indefinite and a callback was set for the advertisment events, this use case is less likely to have
a scan ended callback.

Advertising (if active prior) would be started without regard to it's previous state.
This has been corrected to only start advertising again if it was advertising for an idefinite time.

src/NimBLEAdvertising.h

@@ -95,7 +95,7 @@ public:
 private:
     friend class NimBLEDevice;
 
-    void                    onHostReset();
+    void                    onHostSync();
     static int              handleGapEvent(struct ble_gap_event *event, void *arg);
 
     ble_hs_adv_fields       m_advData;
@@ -108,7 +108,7 @@ private:
     bool                    m_advDataSet;
     void                    (*m_advCompCB)(NimBLEAdvertising *pAdv);
     uint8_t                 m_slaveItvl[4];
-
+    uint32_t                m_duration;
 };
 
 #endif // #if defined(CONFIG_BT_NIMBLE_ROLE_PERIPHERAL)