improve test coverage

[milyin]

to see test coverage run in zenoh-ts directory

yarn start DAEMON test ALL COVERAGE

The current statistic is

------------------------------------------------------------------
File                                         | Branch % | Line % |
------------------------------------------------------------------
 dist/config.js                              |    100.0 |  100.0 |
 dist/encoding.js                            |    100.0 |   97.0 |
 dist/ext/index.js                           |    100.0 |  100.0 |
 dist/ext/serialization.js                   |     61.3 |   72.4 |
 dist/index.js                               |    100.0 |  100.0 |
 dist/key_expr.js                            |     66.7 |   93.5 |
 dist/key_expr/zenoh_keyexpr_wrapper.js      |    100.0 |  100.0 |
 dist/key_expr/zenoh_keyexpr_wrapper_bg.js   |     20.0 |   69.1 |
 dist/key_expr/zenoh_keyexpr_wrapper_bg.wasm |    100.0 |    2.1 |
 dist/liveliness.js                          |      0.0 |   91.9 |
 dist/pubsub.js                              |    100.0 |   64.5 |
 dist/querier.js                             |     27.3 |   76.5 |
 dist/query.js                               |     65.5 |   86.0 |
 dist/remote_api/channels.js                 |     80.0 |   96.7 |
 dist/remote_api/link.js                     |      0.0 |   68.1 |
 dist/remote_api/pubsub.js                   |    100.0 |   47.0 |
 dist/remote_api/querier.js                  |      0.0 |   94.1 |
 dist/remote_api/query.js                    |      0.0 |   81.8 |
 dist/remote_api/session.js                  |     45.2 |   65.3 |
 dist/sample.js                              |      8.0 |   63.1 |
 dist/session.js                             |     14.3 |   64.5 |
 dist/timestamp.js                           |    100.0 |   16.0 |
 dist/z_bytes.js                             |    100.0 |   88.5 |
 tests/src/z_api_pub_sub.ts                  |    100.0 |  100.0 |
 tests/src/z_api_queryable_get.ts            |     15.4 |   88.4 |
 tests/src/z_channels.ts                     |    100.0 |  100.0 |
 tests/src/z_keyexpr.ts                      |    100.0 |  100.0 |
 tests/src/z_liveliness.ts                   |     20.0 |   83.3 |
 tests/src/z_parameters.ts                   |     50.0 |   78.4 |
 tests/src/z_serialization.ts                |    100.0 |  100.0 |
------------------------------------------------------------------
 All files                                   |     44.5 |   71.1 |
------------------------------------------------------------------
Lcov coverage report has been generated at file:///Users/milyin/ZS1/zenoh-ts/zenoh-ts/tests/coverage_profile/lcov.info
HTML coverage report has been generated at file:///Users/milyin/ZS1/zenoh-ts/zenoh-ts/tests/coverage_profile/html/index.html

Need to review the report and ensure that all important functionality is covered