Remove CSSSizeOrAuto completely

Use CSSAuto or CSSSize instead (and overloading when needed)

web/core/src/jsMain/kotlin/androidx/compose/web/css/CSSHelpers.kt

@@ -1,12 +1,10 @@
 @file:Suppress("UNUSED")
 package org.jetbrains.compose.web.css
 
-interface CSSAutoValue : CSSSizeOrAutoValue
+interface CSSAutoValue : StylePropertyValue
 
 val auto = "auto".unsafeCast<CSSAutoValue>()
 
-external interface CSSSizeOrAutoValue : StylePropertyValue
-
 enum class Direction {
     rtl,
     ltr;

web/core/src/jsMain/kotlin/androidx/compose/web/css/CSSUnits.kt

@@ -1,6 +1,6 @@
 package org.jetbrains.compose.web.css
 
-interface CSSSizeValue : CSSUnitValue, CSSSizeOrAutoValue
+interface CSSSizeValue : CSSUnitValue, StylePropertyValue
 
 interface CSSRelValue : CSSSizeValue
 interface CSSpercentValue : CSSRelValue