Fix skiko text helpers visibility (JetBrains#3150)

[CMP-9403](https://youtrack.jetbrains.com/issue/CMP-9403) Remove from
public accidentally exposed convert functions in
`ParagraphBuilder.skiko.kt`

## Release Notes
N/A

Author: MatkovIvan

compose/ui/ui-text/src/skikoMain/kotlin/androidx/compose/ui/text/platform/ParagraphBuilder.skiko.kt

@@ -755,26 +755,13 @@ private fun SpanStyle.copyWithDefaultFontSize(drawStyle: DrawStyle? = null): Spa
     )
 }
 
-// TODO: Remove from public
-@InternalTextApi
-fun FontStyle.toSkFontStyle(): SkFontStyle {
+internal fun FontStyle.toSkFontStyle(): SkFontStyle {
     return when (this) {
         FontStyle.Italic -> SkFontStyle.ITALIC
         else -> SkFontStyle.NORMAL
     }
 }
 
-// TODO: Remove from public
-@Suppress("unused")
-@Deprecated(
-    message = "This method was not intended to be public",
-    level = DeprecationLevel.HIDDEN
-)
-@InternalTextApi
-fun TextDecoration.toSkDecorationStyle(color: Color): SkDecorationStyle {
-    return toSkDecorationStyle(color, null)
-}
-
 private fun TextDecoration.toSkDecorationStyle(
     color: Color,
     textDecorationLineStyle: TextDecorationLineStyle?
@@ -808,9 +795,7 @@ private fun TextDecorationLineStyle.toSkDecorationLineStyle(): SkDecorationLineS
     }
 }
 
-// TODO: Remove from public
-@InternalTextApi
-fun PlaceholderVerticalAlign.toSkPlaceholderAlignment(): PlaceholderAlignment {
+private fun PlaceholderVerticalAlign.toSkPlaceholderAlignment(): PlaceholderAlignment {
     return when (this) {
         PlaceholderVerticalAlign.AboveBaseline -> PlaceholderAlignment.ABOVE_BASELINE
         PlaceholderVerticalAlign.TextTop -> PlaceholderAlignment.TOP