This KB describes the sample config to stop sending unnecessary SNMPv2 traps.

You may want to stop certain unnecessary SNMPv2 traps. In that case, it cannot be achieved with SNMPv2 configuration alone, but it is possible by using SNMPv3.

For example, if you want to stop sending out SNMPv2 MIB jnxCmCfgChange only. 
Here is the sample config, it can filter jnxCmCfgChange.
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set snmp v3 target-address TA address 10.10.10.1
set snmp v3 target-address TA target-parameters TP
set snmp v3 target-parameters TP parameters message-processing-model v2c
set snmp v3 target-parameters TP parameters security-model v2c
set snmp v3 target-parameters TP parameters security-level none
set snmp v3 target-parameters TP parameters security-name SN_v2c
set snmp v3 target-parameters TP notify-filter NF
set snmp v3 notify V2C-NOTIFY type trap
set snmp v3 notify-filter NF oid 1.3.6.1.4.1.2636.4.5.0.1 exclude
set snmp v3 notify-filter NF oid .1 include
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For the details of each parameter, please refer to the document below and modify it accordingly.
https://www.juniper.net/documentation/us/en/software/junos/network-mgmt/topics/topic-map/snmpv3-traps.html