Noisy min-resolved-ts logs when the PD default configuration is min-resolved-ts-persistence-interval=0

[HuSharp]

Bug Report

#43737 introduced a new approach to getting the min-resolved-ts from the PD server by HTTP API. However, 6.1 pd developed the min-resolved-ts collection feature, but the default configuration is min-resolved-ts-persistence-interval=0, that is, off state, subsequent versions to open, which led to 6.1 upgrade to 6.5/7.0/7.1 this configuration is off state, before 7.1 Before 7.1, tidb did not rely on this feature of pd, 7.1 became dependent on this feature, but for the 6.1 upgrade to 7.1 cluster, pd this feature is turned off by default, so brush this error.

But this should not affect the normal use of tidb, because pd does not provide this function, tidb will use the previous path