Validate image preview as URI.

Resolves #13392.

app/src/main/java/org/thoughtcrime/securesms/util/LinkUtil.kt

@@ -2,6 +2,8 @@ package org.thoughtcrime.securesms.util
 
 import okhttp3.HttpUrl
 import org.thoughtcrime.securesms.stickers.StickerUrl
+import java.net.URI
+import java.net.URISyntaxException
 import java.util.Objects
 import java.util.regex.Pattern
 
@@ -37,6 +39,10 @@ object LinkUtil {
       return false
     }
 
+    if (!isValidURI(linkUrl)) {
+      return false
+    }
+
     return HttpUrl.parse(linkUrl)?.scheme() == "https"
   }
 
@@ -85,5 +91,19 @@ object LinkUtil {
     )
   }
 
+  @JvmStatic
+  private fun isValidURI(linkUri: String?): Boolean {
+    return if (linkUri == null) {
+      false
+    } else {
+      try {
+        val ignored = URI(linkUri)
+        true
+      } catch (e: URISyntaxException) {
+        false
+      }
+    }
+  }
+
   private data class LegalCharactersResult(val isLegal: Boolean, val domain: String? = null)
 }