[Task]: Improve input stream parser that creates `anydata` values

[Nadeeshan96]

Description

This issues contains to-do items for the feature introduced by https://github.com/ballerina-platform/ballerina-lang/issues/41824.

• [ ] #42384
• [x] Improve test coverage of the stream parser - to do this we can generate tests using available cloneWithType and fromJsonWithType tests. (i.e. generate strings from values and print the target types)
• [x] Remove JsonParser by adding modes to the StreamParser too. (There are modes in Json parser which says to creates decimals and floats in the relevant places)
• [x] Standardize and edit error messages thrown by stream parser. - We can use stream parser in standard libraries and see what error messages they expect and edit error messages so that we have minimum backward incompatibilities.
• [x] Refactor Stream parser to remove duplicate code
• [x] Add validations for subtypes

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-> Runtime

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