[O11y][AWS] Fix Incorrect fields in AWS Metrics Overview dashboard

[rajvi-patel-22]

• Bug

What does this PR do?

Update AWS Metric visualizations with correct field names.

Old Field	New Field
aws.ec2.cpu.total.pct	host.cpu.usage
aws.elb.metrics.Latency	aws.elb.metrics.Latency.avg
aws.elb.metrics.UnHealthyHostCount	aws.elb.metrics.UnHealthyHostCount.max
aws.lambda.metrics.Invocations	aws.lambda.metrics.Invocations.avg
aws.ecs.metrics.CPUUtilization	aws.ecs.metrics.CPUUtilization.avg
aws.ecs.metrics.CPUReservation	aws.ecs.metrics.CPUReservation.avg

Checklist

• I have reviewed tips for building integrations and this pull request is aligned with them.
• I have verified that all data streams collect metrics or logs.
• I have added an entry to my package's changelog.yml file.
• I have verified that Kibana version constraints are current according to guidelines.

Related issues

• [O11y][AWS] Incorrect fields in AWS Metrics Overview dashboard #6338
• [O11y][AWS Metrics] Lens Migration #6222

Screenshots

[elasticmachine]

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• Start Time: 2023-05-29T03:14:57.804+0000

• Duration: 57 min 10 sec

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Test	Results
Failed	0
Passed	188
Skipped	4
Total	192

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Name	Metrics % (covered/total)	Diff
Packages	100.0% (15/15)	💚
Files	93.75% (15/16)	👎 -4.992
Classes	93.75% (15/16)	👎 -4.992
Methods	86.131% (236/274)	👎 -8.266
Lines	85.925% (7387/8597)	👎 -7.684
Conditionals	100.0% (0/0)	💚

[harnish-crest-data]

LGTM!

[milan-elastic]

LGTM!