MQE: add support for unless

[charleskorn]

What this PR does

This PR adds support for the unless binary operation, building on the support for and added in #9507.

Compared to Prometheus' engine, latency is up to 60% lower and peak memory consumption is up to 48% lower in our benchmarks:

                                                                          │  Prometheus   │               Mimir                │
                                                                          │    sec/op     │   sec/op     vs base               │
Query/a_1_unless_b_1{l=~'.*[0-4]$'},_instant_query-10                        721.4µ ± 12%   716.4µ ± 1%        ~ (p=0.093 n=6)
Query/a_1_unless_b_1{l=~'.*[0-4]$'},_range_query_with_100_steps-10           777.4µ ±  4%   745.8µ ± 6%        ~ (p=0.180 n=6)
Query/a_1_unless_b_1{l=~'.*[0-4]$'},_range_query_with_1000_steps-10          1.310m ±  3%   1.184m ± 3%   -9.67% (p=0.002 n=6)
Query/a_100_unless_b_100{l=~'.*[0-4]$'},_instant_query-10                    1.635m ±  2%   1.631m ± 2%        ~ (p=0.937 n=6)
Query/a_100_unless_b_100{l=~'.*[0-4]$'},_range_query_with_100_steps-10       3.266m ±  1%   2.343m ± 1%  -28.27% (p=0.002 n=6)
Query/a_100_unless_b_100{l=~'.*[0-4]$'},_range_query_with_1000_steps-10     17.681m ±  1%   8.731m ± 2%  -50.62% (p=0.002 n=6)
Query/a_2000_unless_b_2000{l=~'.*[0-4]$'},_instant_query-10                  17.30m ±  2%   17.06m ± 1%   -1.39% (p=0.041 n=6)
Query/a_2000_unless_b_2000{l=~'.*[0-4]$'},_range_query_with_100_steps-10     52.37m ±  1%   30.90m ± 1%  -41.01% (p=0.002 n=6)
Query/a_2000_unless_b_2000{l=~'.*[0-4]$'},_range_query_with_1000_steps-10    402.6m ±  5%   146.5m ± 1%  -63.61% (p=0.002 n=6)

                                                                          │  Prometheus   │                Mimir                │
                                                                          │       B       │      B        vs base               │
Query/a_1_unless_b_1{l=~'.*[0-4]$'},_instant_query-10                        70.76Mi ± 3%   68.78Mi ± 2%   -2.79% (p=0.041 n=6)
Query/a_1_unless_b_1{l=~'.*[0-4]$'},_range_query_with_100_steps-10           69.18Mi ± 2%   68.72Mi ± 3%        ~ (p=0.225 n=6)
Query/a_1_unless_b_1{l=~'.*[0-4]$'},_range_query_with_1000_steps-10          67.70Mi ± 3%   66.66Mi ± 2%        ~ (p=0.065 n=6)
Query/a_100_unless_b_100{l=~'.*[0-4]$'},_instant_query-10                    66.35Mi ± 1%   66.12Mi ± 2%        ~ (p=0.329 n=6)
Query/a_100_unless_b_100{l=~'.*[0-4]$'},_range_query_with_100_steps-10       66.99Mi ± 1%   66.29Mi ± 2%   -1.05% (p=0.026 n=6)
Query/a_100_unless_b_100{l=~'.*[0-4]$'},_range_query_with_1000_steps-10      72.31Mi ± 2%   67.63Mi ± 1%   -6.47% (p=0.002 n=6)
Query/a_2000_unless_b_2000{l=~'.*[0-4]$'},_instant_query-10                  68.11Mi ± 2%   69.30Mi ± 2%        ~ (p=0.065 n=6)
Query/a_2000_unless_b_2000{l=~'.*[0-4]$'},_range_query_with_100_steps-10     83.55Mi ± 2%   73.02Mi ± 2%  -12.61% (p=0.002 n=6)
Query/a_2000_unless_b_2000{l=~'.*[0-4]$'},_range_query_with_1000_steps-10    198.3Mi ± 1%   104.1Mi ± 3%  -47.50% (p=0.002 n=6)

Which issue(s) this PR fixes or relates to

(none)

Checklist

• Tests updated.
• [n/a] Documentation added.
• CHANGELOG.md updated - the order of entries should be [CHANGE], [FEATURE], [ENHANCEMENT], [BUGFIX].
• [n/a] about-versioning.md updated with experimental features.

[jhesketh]

Nice stuff!