fix(curl): trim HTTP response header values (#1675)

Co-authored-by: Claude Opus 4.6 <[email protected]>

Author: jpnurmi

src/transports/sentry_http_transport_curl.c

@@ -3,6 +3,7 @@
 #include "sentry_envelope.h"
 #include "sentry_http_transport.h"
 #include "sentry_options.h"
+#include "sentry_slice.h"
 #include "sentry_string.h"
 #include "sentry_sync.h"
 #include "sentry_transport.h"
@@ -155,10 +156,12 @@ header_callback(char *buffer, size_t size, size_t nitems, void *userdata)
     if (sep) {
         *sep = '\0';
         sentry__string_ascii_lower(header);
+        sentry_slice_t value
+            = sentry__slice_trim(sentry__slice_from_str(sep + 1));
         if (sentry__string_eq(header, "retry-after")) {
-            info->retry_after = sentry__string_clone(sep + 1);
+            info->retry_after = sentry__slice_to_owned(value);
         } else if (sentry__string_eq(header, "x-sentry-rate-limits")) {
-            info->x_sentry_rate_limits = sentry__string_clone(sep + 1);
+            info->x_sentry_rate_limits = sentry__slice_to_owned(value);
         }
     }