🔨 Add src_filter for I2C_AMMETER (#24242)

ini/features.ini

 NEOPIXEL_LED                           = adafruit/Adafruit NeoPixel@~1.8.0
                                          src_filter=+<src/feature/leds/neopixel.cpp>
 I2C_AMMETER                            = peterus/INA226Lib@1.1.2
+                                         src_filter=+<src/feature/ammeter.cpp>
 USES_LIQUIDCRYSTAL                     = LiquidCrystal=https://github.com/MarlinFirmware/New-LiquidCrystal/archive/1.5.1.zip
 USES_LIQUIDCRYSTAL_I2C                 = marcoschwartz/LiquidCrystal_I2C@1.1.4
 USES_LIQUIDTWI2                        = LiquidTWI2@1.2.7

platformio.ini

   -<src/HAL/shared/eeprom_if_i2c.cpp>
   -<src/HAL/shared/eeprom_if_spi.cpp>
   -<src/feature/adc> -<src/gcode/feature/adc>
+  -<src/feature/ammeter.cpp>
   -<src/feature/babystep.cpp>
   -<src/feature/backlash.cpp>
   -<src/feature/baricuda.cpp> -<src/gcode/feature/baricuda>