Remove the old log buffer

[ferglor]

https://smartcontract-it.atlassian.net/browse/AUTO-9355

This PR removes the old log buffer and the corresponding feature flag from the code; we want to use the new buffer by default moving forward

Test results

• Not every block contains logs for each upkeep - this seems to be because we have no control over exactly what logs get emitted and when, as this is up to the geth node
• It seems that some blocks don't contain any logs for certain upkeep, while other blocks contain a number of logs per upkeep, e.g block 1010 and 1011 don't have any logs for upkeep 0, but block 1007 had 5 logs:

"0":{
      "1000":2,
      "1001":2,
      "1002":3,
      "1003":1,
      "1004":1,
      "1005":2,
      "1006":2,
      "1007":5,
      "1008":1,
      "1009":2,
      "1012":1,
      ...

• This PR was created to help gather insights to exactly how many logs were dequeued per upkeep per block
• We were able to measure log availability and the number of logs dequeued, as well as instances of logs missing from certain block ranges, and tracking cleaned/dropped logs
• As an example of logs dequeued, for one upkeep we can see how many logs were dequeued in a selected block range:

{
	"104500045091363938937248279319830213588488308612973768466030697520485050708437": {
		"1902": [
			2
		],
		"1903": [
			2
		],
		"1904": [
			2
		],
		"1905": [
			2
		],
		"1906": [
			2
		],
		"1907": [
			2
		],
		"1908": [
			2
		],
		"1909": [
			2
		],
		"1910": [
			2
		],
		"1938": [
			2
		],
...

• This shows us that 1902-1910 were dequeued from once, and each dequeue was for 2 logs (minimum guaranteed)
• The gap in dequeued blocks between 1910 and 1938 is further evidenced by a lack of available logs in that block range, e.g. a different dataset focuses on log availability per upkeep per block shows no logs were available in that block range:

		"1910": [
			6
		],
		"1938": [
			4
		],

• This shows that for this upkeep, block 1910 had 6 logs available for dequeuing, followed by a gap of availability until block 1938, which had 4 logs available for dequeuing

50x2 upkeeps

	Old buffer	New buffer
Average	48.403181	45.50054
Median	39	36
90th Percentile	100	93
99th Percentile	152	132
Max	283	280
Perform Count Fast Execution:	321176	334311
Total Expected Log Triggering Events:	360000	360000
Total Log Triggering Events Emitted:	360200	360200
Total Events Missed:	706	340
Percent Missed:	0.196002	0.094392

50x10 upkeeps

	Old buffer	New buffer
Average	130.243086	125.347883
Median	126	117
90th Percentile	241	235
99th Percentile	270	276
Max	278	284
Perform Count Fast Execution:	114552	211442
Total Expected Log Triggering Events:	1800000	1800000
Total Log Triggering Events Emitted:	1801000	1801000
Total Events Missed:	1667092	1537481
Percent Missed:	92.564797	85.368184

50x10+1 upkeeps

	Old buffer	New buffer
Average	128.517138	94.876548
Median	122	74
90th Percentile	239	204
99th Percentile	269	268
Max	276	288
Perform Count Fast Execution:	109814	149013
Total Expected Log Triggering Events:	1800000	1800000
Total Log Triggering Events Emitted:	1801000	1801000
Total Events Missed:	1672352	1585082
Percent Missed:	92.856857	88.011216

Node upgrade tests passing: https://github.com/smartcontractkit/chainlink/actions/runs/10010662768/job/27672458705

[infiloop2]

we can probably remove the Lock/unlock completely here since we dont need to read buffer version

[cl-sonarqube-production]

Quality Gate passed

Issues
0 New issues
5 Fixed issues
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
0.0% Duplication on New Code

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