[7.x] useSavedDashboard: call toast methods in their context (#86803)

[afharo]

Backports the following commits to 7.x:

• useSavedDashboard: call toast methods in their context (useSavedDashboard: call toast methods in their context #86803)

[kibanamachine]

💚 Build Succeeded

• continuous-integration/kibana-ci/pull-request
• Commit: 18afd43

Metrics [docs]

Async chunks

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

id	before	after	diff
dashboard	196.8KB	196.7KB	-137.0B
triggersActionsUi	1.6MB	1.5MB	-26.9KB
total			-27.0KB

Distributable file count

id	before	after	diff
default	47486	48249	+763

Page load bundle

Size of the bundles that are downloaded on every page load. Target size is below 100kb

id	before	after	diff
triggersActionsUi	162.5KB	162.6KB	+102.0B

Unknown metric groups

async chunk count

id	before	after	diff
triggersActionsUi	31	32	+1

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