server,common : fix the GCC 12 stringop-overread false positive (again) (#29325)

Signed-off-by: Adrien Gallouët <[email protected]>

common/speculative.cpp

@@ -228,9 +228,7 @@ struct common_speculative_impl_draft_simple : public common_speculative_impl {
             common_params_sampling params;
             params.no_perf = false;
             params.top_k = 10;
-            params.samplers = {
-                COMMON_SAMPLER_TYPE_TOP_K,
-            };
+            params.samplers.assign(1, COMMON_SAMPLER_TYPE_TOP_K);
 
             smpl.reset(common_sampler_init(llama_get_model(ctx_dft), params));
         }

tools/server/server-context.cpp

@@ -2060,7 +2060,7 @@ private:
             res->is_begin = true;
         } else {
             res->content = tkn.text_to_send;
-            res->tokens  = { tkn.tok };
+            res->tokens.assign(1, tkn.tok);
         }
 
         res->n_decoded             = slot.stats.n_gen;