Remove invalid unicode characters from mesh-api/mbed_lib.json

[rwalton-arm]

Summary of changes

mbed-mesh-api/mbed_lib.json contained an invalid unicode character (U+202C).

When attempting to decode this file in a Python script, it fails with a JSONDecodeError.
The current tools ignore encoding errors when opening a file object, masking the problem.

The github file viewer seems to ignore these characters. However, the invalid characters can be seen in a git diff on the command line (shown below).

     "config": {
         "heap-size": {
-            "help": "Nanostack's heap size [bytes: 0-<U+202D>4294967295<U+202C>]",
+            "help": "Nanostack's heap size [bytes: 0-4294967295]",
             "value": 32500
         },
         "mac-neigh-table-size": {
@@ -142,13 +142,13 @@
         },
         "wisun-uc-fixed-channel": {
             "help": "Default 16-bit fixed channel for unicast. Used when channel hopping is not desired.",
-            "value_max": 65535<U+202C>,
-            "value": <U+202D>65535<U+202C>
+            "value_max": 65535,
+            "value": 65535
         },
         "wisun-bc-fixed-channel": {
             "help": "Default 16-bit fixed channel for multicast. Used when channel hopping is not desired.",
-            "value_max": 65535<U+202C>,
-            "value": 65535<U+202C>
+            "value_max": 65535,
+            "value": 65535 

Impact of changes

Migration actions required

Documentation

None

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Pull request type

[x] Patch update (Bug fix / Target update / Docs update / Test update / Refactor)
[] Feature update (New feature / Functionality change / New API)
[] Major update (Breaking change E.g. Return code change / API behaviour change)

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Test results

[x] No Tests required for this change (E.g docs only update)
[] Covered by existing mbed-os tests (Greentea or Unittest)
[] Tests / results supplied as part of this PR

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Reviewers

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[ciarmcom]

@rwalton-arm, thank you for your changes.
@ARMmbed/mbed-os-ipcore @ARMmbed/mbed-os-maintainers please review.

[0xc0170]

CI started

[mbed-ci]

Test run: SUCCESS

Summary: 7 of 7 test jobs passed
Build number : 1
Build artifacts