fix: stop using double slashes in ImdsCredentialsProvider URLs (#1380)

Author: argggh

.changes/5a460540-14ee-4d26-a860-8cd122323b34.json

@@ -0,0 +1,5 @@
+{
+    "id": "5a460540-14ee-4d26-a860-8cd122323b34",
+    "type": "bugfix",
+    "description": "Stop using double slashes in `ImdsCredentialsProvider` URLs"
+}

aws-runtime/aws-config/common/src/aws/sdk/kotlin/runtime/auth/credentials/ImdsCredentialsProvider.kt

@@ -84,7 +84,7 @@ public class ImdsCredentialsProvider(
         }
 
         val payload = try {
-            client.value.get("$CREDENTIALS_BASE_PATH/$profileName")
+            client.value.get("$CREDENTIALS_BASE_PATH$profileName")
         } catch (ex: Exception) {
             return useCachedCredentials(ex) ?: throw CredentialsProviderException("failed to load credentials", ex)
         }

aws-runtime/aws-config/common/test/aws/sdk/kotlin/runtime/auth/credentials/ImdsCredentialsProviderTest.kt

@@ -140,6 +140,8 @@ class ImdsCredentialsProviderTest {
             "IMDSv2",
         )
         assertEquals(expected1, actual1)
+
+        connection.assertRequests()
     }
 
     @Test
@@ -195,6 +197,8 @@ class ImdsCredentialsProviderTest {
             "IMDSv2",
         )
         assertEquals(expected, actual)
+
+        connection.assertRequests()
     }
 
     @Test
@@ -225,6 +229,8 @@ class ImdsCredentialsProviderTest {
         ex.message.shouldContain("failed to load instance profile")
         assertIs<EC2MetadataError>(ex.cause)
         ex.cause!!.message.shouldContain("Request forbidden")
+
+        connection.assertRequests()
     }
 
     @Test
@@ -272,6 +278,8 @@ class ImdsCredentialsProviderTest {
         assertFailsWith<CredentialsProviderException> {
             provider.resolve()
         }.message.shouldContain("failed to load instance profile")
+
+        connection.assertRequests()
     }
 
     // SDK can send a request if expired credentials are available.
@@ -329,6 +337,8 @@ class ImdsCredentialsProviderTest {
         )
 
         assertEquals(expected, actual)
+
+        connection.assertRequests()
     }
 
     @Test