sns: fixup a409dede

vector will not copy when move ctor is marked noexcept
remove the copy ctor 'trick', re-add dtor. explicitly do the thing we want
(...clang-tidy would've shown this issue, something to do in the CI...)

code/espurna/sensor.cpp

@@ -227,14 +227,18 @@ struct sensor_magnitude_t {
     }
 
     sensor_magnitude_t() = delete;
-
     sensor_magnitude_t& operator=(const sensor_magnitude_t&) = default;
-    sensor_magnitude_t(const sensor_magnitude_t&) = default;
-    sensor_magnitude_t(sensor_magnitude_t&& other) {
+
+    sensor_magnitude_t(const sensor_magnitude_t&) = delete;
+    sensor_magnitude_t(sensor_magnitude_t&& other) noexcept {
         *this = other;
         other.filter = nullptr;
     }
 
+    ~sensor_magnitude_t() {
+        delete filter;
+    }
+
     sensor_magnitude_t(unsigned char slot, unsigned char index_local, unsigned char type, sensor::Unit units, BaseSensor* sensor);
 
     BaseSensor * sensor { nullptr }; // Sensor object
@@ -259,6 +263,16 @@ struct sensor_magnitude_t {
 
 };
 
+static_assert(
+    std::is_nothrow_move_constructible<sensor_magnitude_t>::value,
+    "std::vector<sensor_magnitude_t> should be able to work with resize()"
+);
+
+static_assert(
+    !std::is_copy_constructible<sensor_magnitude_t>::value,
+    "std::vector<sensor_magnitude_t> should only use move ctor"
+);
+
 unsigned char sensor_magnitude_t::_counts[MAGNITUDE_MAX] = {0};
 
 namespace sensor {