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refactor(core): update peerDependencies to allow rxjs7 (#42991)

We can't update the framework to rxjs7 until version 13, 
because it contains breaking changes, but we can allow users 
to opt into it since all of our code should be compatible.

These changes expand the allowed version range of rxjs 
and add an integration test to verify that we don't get 
compilation errors. Note that we also have a test that 
runs the AIO examples against rxjs 7 already (#42660).

Fixes #41897.

PR Close #42991

 fix(compiler): include leading whitespace in source-spans of i18n messages (#42062)

Previously, the way templates were tokenized meant that we lost information
about the location of interpolations if the template contained encoded HTML
entities. This meant that the mapping back to the source interpolated strings
could be offset incorrectly.

Also, the source-span assigned to an i18n message did not include leading
whitespace. This confused the output source-mappings so that the first text
nodes of the message stopped at the first non-whitespace character.

This commit makes use of the previous refactorings, where more fine grain
information was provided in text tokens, to enable the parser to identify
the location of the interpolations in the original source more accurately.

Fixes #41034

PR Close #42062