[7.x] [Security Solution] Refactor Network Top Countries to use Search Strategy (#76244)

[patrykkopycinski]

Backports the following commits to 7.x:

• [Security Solution] Refactor Network Top Countries to use Search Strategy ([Security Solution] Refactor Network Top Countries to use Search Strategy #76244)

[kibanamachine]

💚 Build Succeeded

• continuous-integration/kibana-ci/pull-request
• Commit: 8003bc0

Build metrics

@kbn/optimizer bundle module count

id	value	diff	baseline
securitySolution	1941	+2	1939

async chunks size

id	value	diff	baseline
securitySolution	9.8MB	+12.4KB	9.8MB

distributable file count

id	value	diff	baseline
total	47182	+6	47176

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