Revert "ct: Add early max_bytes check to L1 reader"

a0bbe35 made the L1 reader return end-of-stream + no data when
strict_max_bytes && max_bytes==0. In a fetch over many partitions the
plan hands the budget-exhausted tail partitions max_bytes==0 with
strict_max_bytes set (everything after the obligatory first read), so
those partitions now return nothing and never advance -- the consumer
stalls (ManyPartitionsTest cloud_topics times out, a regression since
late March). Before the check they got a trickle and drained.

Reverting to verify the regression via CDT; a proper fix that keeps the
no-wasteful-read intent without starving the tail follows.

Author: oleiman

src/v/cloud_topics/level_one/frontend_reader/level_one_reader.cc

@@ -117,11 +117,6 @@ level_one_log_reader_impl::open_reader_at(
 ss::future<model::record_batch_reader::storage_t>
 level_one_log_reader_impl::read_some(
   model::timeout_clock::time_point deadline) {
-    if (_config.strict_max_bytes && _config.max_bytes == 0) {
-        set_end_of_stream();
-        co_await close_current_stream();
-        co_return model::record_batch_reader::storage_t{};
-    }
     while (true) {
         if (_next_offset > _config.max_offset) {
             vlog(