config: fix use after free error

The doc strings in configuration entries cannot be temporaries (e.g. they
cannot be a fmt::format(...)) string because the configuration structures store
std::string_view. This will lead to sanitizer error like this:

```
819955: ==819957==ERROR: AddressSanitizer: heap-use-after-free on address 0x611000011fc0 at pc 0x5603f697f78a bp 0x7fd04ae85a90 sp 0x7fd04ae85a88
819955: READ of size 1 at 0x611000011fc0 thread T0
819955:     #0 0x5603f697f789 in std::__1::pair<char const*, char*> std::__1::__uninitialized_copy_n<char, char const*, unsigned long, char*, std::__1::__unreachable_sentinel>(char const*, unsigned long, char*, std::__1::__unreachable_sentinel) /home/nwatkins/src/redpanda/vbuild/llvm/install/bin/../include/c++/v1/__memory/uninitialized_algorithms.h:77:51
...
819955:     redpanda-data#14 0x5603f6b9f37f in seastar::basic_sstring<char, unsigned int, 15u, true> ssx::sformat<std::__1::basic_string_view<char, std::__1::char_traits<char>>&, config::base_property const&, std::__1::basic_string_view<char, std::__1::char_traits<char>> const&>(fmt::v8::basic_format_string<char, fmt::v8::type_identity<std::__1::basic_string_view<char, std::__1::char_traits<c
har>>&>::type, fmt::v8::type_identity<config::base_property const&>::type, fmt::v8::type_identity<std::__1::basic_string_view<char, std::__1::char_traits<char>> const&>::type>, std::__1::basic_string_view<char, std::__1::char_traits<char>>&, config::base_property const&, std::__1::basic_string_view<char, std::__1::char_traits<char>> const&) /home/nwatkins/src/redpanda/src/v/ssx/s
format.h:62:5
819955:     redpanda-data#15 0x5603f673b6c9 in auto auto application::hydrate_config(boost::program_options::variables_map const&)::$_11::operator()<config::configuration>(std::__1::basic_string_view<char, std::__1::char_traits<char>>, config::configuration const&) const::'lambda'(config::configuration const&)::operator()<config::base_property>(config::configuration const&) const /home/nwatki
ns/src/redpanda/src/v/redpanda/application.cc:533:15
```

Signed-off-by: Noah Watkins <[email protected]>

Author: dotnwat

src/v/config/configuration.cc

@@ -1568,24 +1568,18 @@ configuration::configuration()
   , kafka_throughput_limit_node_in_bps(
       *this,
       "kafka_throughput_limit_node_in_bps",
-      fmt::format(
-        "Node wide throughput ingress limit - maximum kafka traffic throughput "
-        "allowed on the ingress side of each node, in bytes/s. Default is no "
-        "limit. Effective minimum is 1bps*#cores. Effective maximum is "
-        "{}bps*#cores.",
-        bottomless_token_bucket::max_quota),
+      "Node wide throughput ingress limit - maximum kafka traffic throughput "
+      "allowed on the ingress side of each node, in bytes/s. Default is no "
+      "limit.",
       {.needs_restart = needs_restart::no, .visibility = visibility::user},
       std::nullopt,
       {.min = 1})
   , kafka_throughput_limit_node_out_bps(
       *this,
       "kafka_throughput_limit_node_out_bps",
-      fmt::format(
-        "Node wide throughput egress limit - maximum kafka traffic throughput "
-        "allowed on the egress side of each node, in bytes/s. Default is no "
-        "limit. Effective minimum is 1bps*#cores. Effective maximum is "
-        "{}bps*#cores.",
-        bottomless_token_bucket::max_quota),
+      "Node wide throughput egress limit - maximum kafka traffic throughput "
+      "allowed on the egress side of each node, in bytes/s. Default is no "
+      "limit.",
       {.needs_restart = needs_restart::no, .visibility = visibility::user},
       std::nullopt,
       {.min = ss::smp::count})