Update pfsense_counter.py

[countingpine]

Fix pfSense Firewall Packet Rates formatting to display e.g. 44.91 pkts instead of %.2f pkts.

Old output example:
Values averaged over 3 min, Packets that matched a rule: %.2f pkts, Packets with bad offset: %.2f pkts, Fragmented packets: %.2f pkts, Short packets: %.2f pkts, Normalized packets: %.2f pkts, Packets dropped due to memory limitations: %.2f pkts

New output example:
Values averaged over 3 min, Packets that matched a rule: 42.06 pkts, Packets with bad offset: 0.00 pkts, Fragmented packets: 0.00 pkts, Short packets: 0.00 pkts, Normalized packets: 0.00 pkts, Packets dropped due to memory limitations: 0.00 pkts

I think these SNMP fields will be enough to test the check.

.1.3.6.1.2.1.1.1.0 = "Netgate pfSense Plus myfirewall.test.local 25.07.1-RELEASE FreeBSD 15.0-CURRENT amd64"
.1.3.6.1.4.1.12325.1.200.1.2.1.0 = 42616538
.1.3.6.1.4.1.12325.1.200.1.2.2.0 = 0
.1.3.6.1.4.1.12325.1.200.1.2.3.0 = 1
.1.3.6.1.4.1.12325.1.200.1.2.4.0 = 34
.1.3.6.1.4.1.12325.1.200.1.2.5.0 = 65
.1.3.6.1.4.1.12325.1.200.1.2.6.0 = 0

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