Misleading MissingFieldException on unexpected enum with coerceInputValues

[gmk57]

Describe the bug
Json configuration option coerceInputValues = true is very helpful to future-proof network code, but it has some unfortunate side effects. Some of them are already raised in different issues, but this one is not (AFAIK):

When model has enum field with no default, and unexpected enum value is encountered, confusing MissingFieldException is thrown instead of correct exception with helpful error message. This caught me off-guard a couple times, causing time wasted looking for typos in field name, etc.

To Reproduce

@Test
fun `GIVEN json with unexpected enum value WHEN deserialize THEN throw meaningful exception`() {
    val jsonWithUnexpectedValue = """
        {
            "color": "SOMETHING_UNEXPECTED"
        }
    """.trimIndent()
    val jsonSerializer = Json {
        coerceInputValues = true
    }
    val throwable = runCatching {
        jsonSerializer.decodeFromString<Model>(jsonWithUnexpectedValue)
    }.exceptionOrNull()

    assertThat(throwable, instanceOf(SerializationException::class.java))
    assertThat(throwable!!.message, containsString("SOMETHING_UNEXPECTED"))
}

@Serializable
data class Model(val color: Color)

enum class Color { RED, GREEN }

Expected behavior
kotlinx.serialization.SerializationException: gmk57.Color does not contain element with name 'SOMETHING_UNEXPECTED' at path $.color
That's what is thrown with coerceInputValues = false

Observed behavior
kotlinx.serialization.MissingFieldException: Field 'color' is required for type with serial name 'gmk57.Model', but it was missing at path: $

Environment

• Kotlin version: 1.9.10
• Library version: 1.6.2

I guess the root cause is the same as in #1947, but the issue we face is a bit different.

[gmk57]

Thanks for fixing it! 👍