[7.x] [Maps][Vega] Tidy up mapbox-gl imports (#99733)

[thomasneirynck]

Backports the following commits to 7.x:

• [Maps][Vega] Tidy up mapbox-gl imports ([Maps][Vega] Tidy up mapbox-gl imports #99733)

[kibanamachine]

💚 Build Succeeded

• continuous-integration/kibana-ci/pull-request
• Commit: d71a7dc
• Storybooks Preview

Metrics [docs]

Module Count

Fewer modules leads to a faster build time

id	before	after	diff
visTypeVega	241	243	+2

Async chunks

Total size of all lazy-loaded chunks that will be downloaded as the user navigates the app

id	before	after	diff
visTypeVega	2.6MB	2.6MB	-71.1KB

Unknown metric groups

miscellaneous assets size

id	before	after	diff
visTypeVega	0.0B	550.3KB	⚠️ +550.3KB

References to deprecated APIs

id	before	after	diff
canvas	29	25	-4
crossClusterReplication	8	6	-2
fleet	4	2	-2
globalSearch	4	2	-2
indexManagement	12	7	-5
infra	5	3	-2
licensing	18	15	-3
monitoring	109	56	-53
total			-73

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@elasticmachine merge upstream