Fix crash when expanding raw PSBT card

The Text had a verticalScroll modifier but the parent Column has no
bounded height, so Compose threw IllegalStateException on draw. Long
hex wraps naturally; no inner scroll needed.

https://claude.ai/code/session_01LBVtkHSfr3NDRnYHeyPVVP

app/src/main/java/com/greenart7c3/nostrsigner/ui/components/SignPsbt.kt

@@ -8,8 +8,6 @@ import androidx.compose.foundation.layout.Spacer
 import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.layout.size
-import androidx.compose.foundation.rememberScrollState
-import androidx.compose.foundation.verticalScroll
 import androidx.compose.material3.Card
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Text
@@ -232,9 +230,7 @@ private fun RawPsbtCard(psbtHex: String) {
             if (expanded) {
                 Text(
                     psbtHex,
-                    modifier = Modifier
-                        .fillMaxWidth()
-                        .verticalScroll(rememberScrollState()),
+                    modifier = Modifier.fillMaxWidth(),
                     fontSize = 12.sp,
                 )
             }