[CI] Consolidate some tests (K, L) (#8201)

tests/components/lcd_pcf8574/common.yaml

@@ -0,0 +1,22 @@
+i2c:
+  - id: i2c_lcd_pcf8574
+    scl: ${scl_pin}
+    sda: ${sda_pin}
+
+display:
+  - platform: lcd_pcf8574
+    dimensions: 18x4
+    address: 0x3F
+    user_characters:
+      - position: 0
+        data:
+          - 0b00000
+          - 0b01010
+          - 0b00000
+          - 0b00100
+          - 0b00100
+          - 0b10001
+          - 0b01110
+          - 0b00000
+    lambda: |-
+      it.print("Hello World!");