chore(drawables): drop unused ic_sensors, ic_video, earth_plus

These three vector drawables had no remaining references after the
Material Symbols migration. ic_sensors and ic_video were already
unused; earth_plus was only self-referenced in its own header comment.

https://claude.ai/code/session_016gV9gEaSud6kDMdcaqy8ti

amethyst/src/main/res/drawable/earth_plus.xml

@@ -1 +0,0 @@
-<!-- drawable/earth_plus.xml --><vector xmlns:android="http://schemas.android.com/apk/res/android" android:height="24dp" android:width="24dp" android:viewportWidth="24" android:viewportHeight="24"><path android:fillColor="#000000" android:pathData="M17 14H19V17H22V19H19V22H17V19H14V17H17V14M20 12C20 8.64 17.93 5.77 15 4.59V5C15 6.1 14.1 7 13 7H11V9C11 9.55 10.55 10 10 10H8V12H14C14.5 12 14.9 12.35 15 12.81C13.2 13.85 12 15.79 12 18C12 19.5 12.54 20.85 13.44 21.9L12 22C6.5 22 2 17.5 2 12C2 6.5 6.5 2 12 2C17.5 2 22 6.5 22 12L21.9 13.44C21.34 12.96 20.7 12.59 20 12.34L20 12M11 19.93V18C9.9 18 9 17.1 9 16V15L4.21 10.21C4.08 10.78 4 11.38 4 12C4 16.08 7.06 19.44 11 19.93Z" /></vector>

amethyst/src/main/res/drawable/ic_sensors.xml

@@ -1,10 +0,0 @@
-<vector xmlns:android="http://schemas.android.com/apk/res/android"
-    android:width="48dp"
-    android:height="48dp"
-    android:viewportWidth="960"
-    android:viewportHeight="960">
-  <path
-      android:fillColor="#9c9c9c"
-      android:pathData="M142.11,817.89Q77.63,753.42 40.02,666.86 2.41,580.29 2.41,480q0,-100.29 37.61,-186.86 37.61,-86.56 102.08,-151.04l51.34,51.34q-54.92,54.92 -87.16,128.35 -32.24,73.43 -32.24,158.2 0,84.77 31.64,157.6 31.64,72.83 87.76,128.95zM277.03,682.97q-38.21,-38.21 -60.89,-90.14 -22.69,-51.94 -22.69,-112.83 0,-60.89 22.69,-112.83 22.69,-51.94 60.89,-90.14l51.34,51.34q-28.66,28.66 -45.97,67.46 -17.31,38.8 -17.31,84.17 0,45.37 16.72,83.58 16.72,38.21 46.56,68.06zM480,575.52q-39.4,0 -67.46,-28.06 -28.06,-28.06 -28.06,-67.46 0,-39.4 28.06,-67.46 28.06,-28.06 67.46,-28.06 39.4,0 67.46,28.06 28.06,28.06 28.06,67.46 0,39.4 -28.06,67.46 -28.06,28.06 -67.46,28.06zM682.97,682.97 L631.63,631.63q28.66,-28.66 45.97,-67.46 17.31,-38.8 17.31,-84.17 0,-45.37 -16.72,-83.58 -16.72,-38.21 -46.56,-68.06l51.34,-51.34q38.21,38.21 60.89,90.14 22.69,51.94 22.69,112.83 0,59.7 -22.69,111.64 -22.69,51.94 -60.89,91.34zM817.89,817.89 L766.55,766.55q54.92,-54.92 87.16,-128.35 32.24,-73.43 32.24,-158.2 0,-84.77 -31.64,-157.6 -31.64,-72.83 -87.76,-128.95l51.34,-51.34q64.47,65.67 102.08,152.23 37.61,86.56 37.61,185.66 0,99.1 -37.61,185.66 -37.61,86.56 -102.08,152.23z"
-      android:strokeWidth="1.19396"/>
-</vector>

amethyst/src/main/res/drawable/ic_video.xml

@@ -1,9 +0,0 @@
-<vector xmlns:android="http://schemas.android.com/apk/res/android"
-    android:width="122.88dp"
-    android:height="111.34dp"
-    android:viewportWidth="122.88"
-    android:viewportHeight="111.34">
-  <path
-      android:fillColor="#FF9C9C9C"
-      android:pathData="M23.59,0h75.7a23.68,23.68 0,0 1,23.59 23.59L122.88,87.75A23.56,23.56 0,0 1,116 104.41l-0.22,0.2a23.53,23.53 0,0 1,-16.44 6.73L23.59,111.34a23.53,23.53 0,0 1,-16.66 -6.93l-0.2,-0.22A23.46,23.46 0,0 1,0 87.75L0,23.59A23.66,23.66 0,0 1,23.59 0ZM54,47.73 L79.25,65.36a3.79,3.79 0,0 1,0.14 6.3L54.22,89.05a3.75,3.75 0,0 1,-2.4 0.87A3.79,3.79 0,0 1,48 86.13L48,50.82h0A3.77,3.77 0,0 1,54 47.73ZM7.35,26.47h14L30.41,7.35L23.59,7.35A16.29,16.29 0,0 0,7.35 23.59v2.88ZM37.05,7.35 L28,26.47L53.36,26.47L62.43,7.38v0ZM69.05,7.35L59.92,26.47h24.7L93.7,7.35ZM100.37,7.35L91.26,26.47h24.27L115.53,23.59a16.32,16.32 0,0 0,-15.2 -16.21ZM115.57,34.03L7.35,34.03L7.35,87.75A16.21,16.21 0,0 0,12 99.05l0.17,0.16A16.19,16.19 0,0 0,23.59 104h75.7a16.21,16.21 0,0 0,11.3 -4.6l0.16,-0.18a16.17,16.17 0,0 0,4.78 -11.46L115.53,34.06Z"/>
-</vector>