Update arduino_nano_r3_connector.dtsi for pins 7,8,18,19,21

To match the pins as shown on the pinout page for the NANO 33 BLE SENSE

Tested with simple Arduino sketch:
```
int blink_pin = 2;

void setup() {
  pinMode(LED_BUILTIN, OUTPUT);
  for (uint8_t i=0; i < 4; i++) {
    digitalWrite(LED_BUILTIN, HIGH);
    delay(100);
    digitalWrite(LED_BUILTIN, LOW);
    delay(100);
  }
  pinMode(LED_BUILTIN, INPUT);
  Serial.begin(115200);
  while (!Serial) {}
  Serial.println("Quick blink pin test");
  Serial.println (blink_pin);
  pinMode(blink_pin, OUTPUT);
  Serial.print("LED_BUILTIN: ");
  Serial.println(LED_BUILTIN);
}

void loop() {
  digitalWrite(blink_pin, HIGH);
  delay(250);
  digitalWrite(blink_pin, LOW);
  delay(250);
  if (Serial.available()) {
    int new_pin = Serial.parseInt();
    while (Serial.read() != -1) {
      pinMode(blink_pin, INPUT);
      blink_pin = new_pin;
      pinMode(blink_pin, OUTPUT);
      Serial.print("New pin: ");
      Serial.println(blink_pin);
    }
  }
}
```
Where you can type in a pin number and then jumper that pin to D13 and it should blink the LED.
Fixed it for most of these pins, although 18 and 19 have issue with not blinking as zephyr has those
pins in use.

Author: KurtE

boards/arduino/nano_33_ble/arduino_nano_r3_connector.dtsi

@@ -16,8 +16,8 @@
 			   <4 0 &gpio1 15 0>,  /* D4 */
 			   <5 0 &gpio1 13 0>,  /* D5 */
 			   <6 0 &gpio1 14 0>,  /* D6 */
-			   <7 0 &gpio0 9 0>,   /* D7 */
-			   <8 0 &gpio0 10 0>,  /* D8 */
+			   <7 0 &gpio0 23 0>,   /* D7 */
+			   <8 0 &gpio0 21 0>,  /* D8 */
 			   <9 0 &gpio0 27 0>,  /* D9 */
 			   <10 0 &gpio1 2 0>,  /* D10 */
 			   <11 0 &gpio1 1 0>,  /* D11 / SPI-MOSI */
@@ -27,10 +27,10 @@
 			   <15 0 &gpio0 5 0>,  /* D15 / A1 */
 			   <16 0 &gpio0 30 0>, /* D16 / A2 */
 			   <17 0 &gpio0 29 0>, /* D17 / A3 */
-			   <18 0 &gpio0 14 0>, /* D18 / A4 / I2C-SDA */
-			   <19 0 &gpio0 15 0>, /* D19 / A5 / I2C-SCL */
+			   <18 0 &gpio0 31 0>, /* D18 / A4 / I2C-SDA */
+			   <19 0 &gpio0 2 0>, /* D19 / A5 / I2C-SCL */
 			   <20 0 &gpio0 28 0>, /* D20 / A6 */
-			   <21 0 &gpio1 3 0>;  /* D21 / A7 */
+			   <21 0 &gpio0 3 0>;  /* D21 / A7 */
 	};
 };