[APM] Remove hardcoded values for data streams

[sorenlouv]

Related: #88329

Data streams are currently hardcoded in:

kibana/x-pack/plugins/apm/server/index.ts

Lines 103 to 122 in 8f7e10a

	// Add data stream indices to list of configured values
	mergedConfig[
	'apm_oss.transactionIndices'
	] = `traces-apm*,${mergedConfig['apm_oss.transactionIndices']}`;
	mergedConfig[
	'apm_oss.spanIndices'
	] = `traces-apm*,${mergedConfig['apm_oss.spanIndices']}`;
	mergedConfig[
	'apm_oss.errorIndices'
	] = `logs-apm*,${mergedConfig['apm_oss.errorIndices']}`;
	mergedConfig[
	'apm_oss.metricsIndices'
	] = `metrics-apm*,${mergedConfig['apm_oss.metricsIndices']}`;
	mergedConfig[
	'apm_oss.indexPattern'
	] = `traces-apm*,logs-apm*,metrics-apm*,${mergedConfig['apm_oss.indexPattern']}`;

This should be removed to make it possible to specify data streams with name spaces

New defaults:

• Transactions: traces-apm*, apm-*-transaction-*

[elasticmachine]

Pinging @elastic/apm-ui (Team:apm)