use utiltimer in memberlist client

[SungJin1212]

Similar to #7270, this PR utilizes a utiltimer in the memberlist client to reuse the timer.

Benchmark results

goos: darwin
goarch: arm64
pkg: github.com/cortexproject/cortex/pkg/ring/kv/memberlist
cpu: Apple M4 Max
                      │   old.txt   │            new.txt             │
                      │   sec/op    │   sec/op     vs base           │
CASTimerAllocation-14   2.001 ± ∞ ¹   2.001 ± ∞ ¹  ~ (p=1.000 n=1) ²
¹ need >= 6 samples for confidence interval at level 0.95
² need >= 4 samples to detect a difference at alpha level 0.05

                      │    old.txt    │             new.txt              │
                      │     B/op      │     B/op       vs base           │
CASTimerAllocation-14   402.0Ki ± ∞ ¹   355.5Ki ± ∞ ¹  ~ (p=1.000 n=1) ²
¹ need >= 6 samples for confidence interval at level 0.95
² need >= 4 samples to detect a difference at alpha level 0.05

                      │   old.txt   │            new.txt             │
                      │  allocs/op  │  allocs/op   vs base           │
CASTimerAllocation-14   789.0 ± ∞ ¹   752.0 ± ∞ ¹  ~ (p=1.000 n=1) ²
¹ need >= 6 samples for confidence interval at level 0.95
² need >= 4 samples to detect a difference at alpha level 0.05

Which issue(s) this PR fixes:
Fixes #

Checklist

• Tests updated
• Documentation added
• CHANGELOG.md updated - the order of entries should be [CHANGE], [FEATURE], [ENHANCEMENT], [BUGFIX]